Smart Contracts

  • Contract structure

  • Variables

  • Nested Contracts

  • File upload

  • Queries in JSON format

  • Queries with date and time operations

  • Needle contracts language

  • Needle functions classification

  • Needle functions reference

  • System contracts

Smart Contract (hereinafter referred to as Contract) is one of the basic elements of an application. The implementation of a contract on a page by the user is usually a single operation that the purpose is to update or create a database entry. All data operations of an application form a contract system, and these contracts interact with each other through database or contract content functions.

Contract Structure

Use the keyword contract to declare a contract, followed by the contract name, and the contract content must be enclosed in braces. A contract mainly consists of three sections:

  1. data - data section, where declares the variables of the input data, including variable name and variable type;

  2. conditions - conditions section, where validates the correctness of the data;

  3. action - operation section, where defines the data manipulations.

contract MyContract {
    data {
          FromId int
          ToId int
          Amount money
       }
       func conditions {
          ...
       }
       func action {
          ...
       }
    }

Data section

The data section describes the contract data inputs and the form parameters received.

The structure of each line by sequence:

  • Variable name - only receive variables, not arrays;

  • Variable data type - the data type of the variable;

  • optional - an optional parameter that do not need to fill in the form element.

contract my {
 data {
 Name string
 RequestId int
 Photo file "optional"
 Amount money
 Private bytes
 }
 ...
}

Conditions section

The conditions section describes the validation of data received.

The following commands are used for error warnings: serious errors error, warning errors warning, suggestive errors info. These three commands will generate an error that terminates the execution of contracts, and each error will print a different type of error log information. For example:

if fuel == 0 { error "fuel cannot be zero!" } if money <limit { warning Sprintf("You don't have enough money: %v <%v", money, limit) } if idexist > 0 { info "You have already been registered" }

Action section

The action section describes the main code of the contract, which retrieves other data and records the result values in tables. For example:

action {
DBUpdate("keys", $key_id, {"-amount": $amount})
DBUpdate("keys", $recipient, {"+amount": $amount, "pub": $Pub})
}

Variables

Variables declared in the data section are passed to other contract sections through the $ symbol followed by the variable name. The $ symbol can also be used to declare other variables that are not within the data section, which are considered as global variables of this contract and all contracts that this contract is nested.

Pre-defined variables can be used in contracts, which contain transaction data that called the contract:

  • $time - transaction timestamp;

  • $ecosystem_id - ecosystem ID;

  • $block - ID of the block containing the transaction;

  • $key_id - address of the account that signed the current transaction;

  • $type - contract ID in the virtual machine;

  • $block_key_id - account address of the node generated the block;

  • $block_time - block generation timestamp;

  • $original_contract - name of the contract that initially processed the transaction. It means the contract is called during transaction validation if the variable is an empty string. To check whether the contract is called by another contract or directly by the transaction, you need to compare the values of $original_contract and $this_contract. It means that the contract is called by the transaction if they are equal;

  • $this_contract - name of the contract currently being executed;

  • $guest_key - guest account address;

  • $stack - contract array stack with a data type of array, containing all contracts executed. The first element of the array represents the name of the contract currently being executed, while the last element represents the name of the contract that initially processed the transaction;

  • $node_position - the index number of the verification node array where the block is located;

  • $txhash - transaction hash;

  • $contract - the current contract structure array.

Predefined variables can be accessed not only in contracts, but also in permission fields that defines the access permission conditions of the application elements. When used in permission fields, predefined variables for block information are always equal to zero, such as $time, $block, etc.

A predefined variable $result is assigned with the return result of the contract.

contract my {
 data {
     Name string
     Amount money
 }
 func conditions {
     if $Amount <= 0 {
     error "Amount cannot be 0"
     }
     $ownerId = 1232
 }
 func action {
     var amount money
     amount = $Amount - 10
     DBUpdate("mytable", $ownerId, {name: $Name,amount: amount})
     DBUpdate("mytable2", $ownerId, {amount: 10})
 }
}

Nested Contracts

You can nest contracts in the conditions and action sections of the contract. Nested contracts can be called directly, and the contract parameters are specified in parentheses after the contract name, for example, @1NameContract(Params). You may also call nested contracts with the CallContract function.

File upload

To upload a file using a form in the format of multipart/form-data, the data type of the contract must be file.

contract Upload {
     data {
  	   File file
     }
     ...
}

The UploadBinary contract is used to upload and store files. With the Logicor language function Binary in the page editor, you can get the file download link.

Queries in JSON format

In the contract language, JSON can be specified as a field type. You can use the syntax: columnname->fieldname to process the entry field. The value obtained is recorded in columnname.fieldname. The above syntax can be used in Columns,One,Where of the DBFind function.

var ret map
var val str
var list array
ret = DBFind("mytable").Columns("myname,doc,doc->ind").WhereId($Id).Row()
val = ret["doc.ind"]
val = DBFind("mytable").Columns("myname,doc->type").WhereId($Id).One("doc->type")
list = DBFind("mytable").Columns("myname,doc,doc->ind").Where("doc->ind = ?", "101")
val = DBFind("mytable").WhereId($Id).One("doc->check")

Queries with date and time operations

You cannot directly query and update the date and time with the contract language functions, but you can use PostgreSQL functions and features in the Where statement as in the example below. For example, you need to compare the field date_column with the current time. If date_column is a timestamp type, the expression should be date_column <NOW(); if date_column is a Unix type, the expression should be to_timestamp(date_column)> NOW().

Where("to_timestamp(date_column)> NOW()")
Where("date_column <NOW() - 30 * interval '1 day'")

The following Needle function is used to process date and time in SQL format:

  • BlockTime

  • DateTime

  • UnixDateTime

Needle contract language

The contract language includes a set of functions, operators and structures, which can realize data algorithm processing and database operations.

The contract content can be modified if the contract editing permission is not set to false. The complete history of contract changes is stored in the blockchain, which is available in Weaver.

Data operations in the blockchain are executed in accordance with the latest version of the contract.

Basic elements and structure

Data types and variables

Data type must be defined for every variables. Normally, data types are converted automatically. The following data types can be used:

  • bool - Boolean, true or false;

  • bytes - a byte format;

  • Int - a 64-bit integer;

  • Array - an array of any type;

  • map - an object array;

  • money - a big integer;

  • float - a 64-bit float number;

  • string - a string must be defined with double quotes or escape format: "This is a string" or This is a string;

  • file - an object array:

  • Name - file name, string type;

  • MimeType - mime-type file, string type;

  • Body - file content, bytes type.

All identifiers, including the names of variables, functions and contracts, are case sensitive (MyFunc and myFunc are different names).

Use the var keyword to declare a variable, followed by the name and type of the variable. Variables declared in braces must be used in the same pair of braces.

The default value of any variable declared is zero: the zero value of bool type is false, the zero value of all numeric types is 0, and the zero value, for strings, empty strings. An example of variable declaration:

func myfunc( val int) int {
 var mystr1 mystr2 string, mypar int
 var checked bool
 ...
 if checked {
 var temp int
 ...
 }
}

Array

The contract language supports two array types:

  • Array - an array with index starting from 0;

  • map - an array of objects.

When allocating and retrieving array elements, the index must be placed in square brackets. Multiple indexes are not supported in the array, and the array elements cannot be treated as myarr[i][j].

var myarr array
var mymap map
var s string

myarr[0] \= 100
myarr[1] \= "This is a line"
mymap["value"] \= 777
mymap["param"] \= "Parameter"

s \= Sprintf("%v, %v, %v", myarr[0] + mymap["value"], myarr[1], mymap["param"])
// s \= 877, This is a line, Parameter

You can also define arrays of array type by specifying elements in []. For map type arrays, please use {}.

var my map
my={"key1": "value1", key2: i, "key3": $Name}
var mya array
mya=["value1", {key2: i}, $Name]

You can use such initialization in expressions. For example, use it in function parameters.

DBFind...Where({id: 1})

For an array of objects, you must specify a key. Key are specified as strings in double quotes (""). If the key name is limited to letters, numbers and underscores, you can omit the double quotes.

{key1: "value1", key2: "value2"}

An array can contain strings, numbers, variable names of any type, and variable names with the $ symbol. It supports nested arrays. You can specify different maps or arrays as values.

Expressions cannot be used as array elements. Use a variable to store the expression result and specify this variable as an array element.

[1+2, myfunc(), name["param"]] // don't do this
[1, 3.4, mystr, "string", $ext, myarr, mymap, {"ids": [1,2, i], company: {"Name": "MyCompany"}} ] // this is ok

var val string
val = my["param"]
MyFunc({key: val, sub: {name: "My name", "color": "Red"}})

If and While statements

The contract language supports standard if conditional statements and while loops, which can be used in contracts and functions. These statements can be nested within each other.

if and while must be followed by a conditional statement. If the conditional statement returns a number, it is regarded as false when its value is 0.

val == 0 is equal to !val, val != 0 is equal to val. The if statement can have an else code block, and the else is executed when the if conditional statement is false.

The following comparison operators can be used in conditional statements: <, >, >=, <=, ==, !=, ||, &&

if val> 10 || id != $block_key_id {
 ...
} else {
 ...
}

The code block is executed when the conditional statement of the while loop is true. break means to terminate the loop of the code block. If you want to start a loop from the beginning, use continue.

var i int
while true {
 if i > 100 {
 break
 }
 ...
 if i \== 50 {
 continue
 }
 ...
 i \= i + 1
}

In addition to conditional statements, Needle also supports standard arithmetic operations: +, -, *, /.

Variables of string and bytes types can be used as a conditional statement. If the length of the type is greater than zero, the condition is true, otherwise it is false.

Functions

Functions can perform some operations on the data received by the data section of a contract: read and write data from the database, convert the type of value, and establish the interaction between contracts.

Function declaration

Use the func keyword to declare a function, followed by the name and the list of parameters passed to it and their types. All parameters are enclosed in parentheses and separated by commas. After the parentheses, the data type of the value returned by the function must be declared. The function body must be enclosed in braces. If the function has no parameters, the braces can be omitted. To return a value from a function, use the return keyword.

func myfunc(left int, right int) int {
 return left*right + left - right
}
func test int {
 return myfunc(10, 30) + myfunc(20, 50)
}
func ooops {
 error "Ooops..."
}

Function do not return errors, because all error checks are performed automatically. If there is an error in any function, the contract will terminate its operation and present the error description in a window.

Variable-length parameters

Functions can define variable-length parameters, use the ... symbol as the last parameter type of the function to indicate variable-length parameters, with a data type of array. Variable-length parameters include all variables from the time the parameter is passed in the call. All types of variables can be passed, but you need to deal with conflicts of mismatching of data types.

func sum(out string, values ...) {
 var i, res int

while i <Len(values) {

   res \= res + values\[i\]

   i \= i + 1

}

Println(out, res)

}

func main() {
 sum("Sum:", 10, 20, 30, 40)
}

Optional parameters

A function has many parameters, but we only need some of them when calling it. In this case, you can declare optional parameters in the following way: func myfunc(name string).Param1(param string).Param2(param2 int) {...}, then you can call the specified parameters in any order: myfunc("name").Param2(100).

In the function body, you can handle these variables normally. If no specified optional parameters called, their default values are zero. You can also use ... to specify a variable-length parameter: func DBFind(table string).Where(request string, params ...) and then call it: DBFind("mytable").Where({" id": $myid, "type": 2})

func DBFind(table string).Columns(columns string).Where(format string, tail ...)
 .Limit(limit int).Offset(offset int) string {
 ...
}

func names() string {
 ...
 return DBFind("table").Columns("name").Where({"id": 100}).Limit(1)
}

Needle functions classification

Retrieving values from the database:

AppParam

EcosysParam

GetDataFromXLSX

DBFind

GetHistory

GetDataFromXLSX

DBRow

GetHistoryRow

GetBlock

DBSelectMetrics

GetColumnType

LangRes

Updating data in tables:

DBInsert

DBUpdateExt

DelTable

DBUpdate

DelColumn

Operations with arrays:

Append

Len

GetMapKeys

Join

Row

SortedKeys

Split

One

Operations with contracts and permissions:

CallContract

GetContractById

TransactionInfo

ContractAccess

RoleAccess

Throw

ContractConditions

GetContractByName

ValidateCondition

EvalCondition

Operations with addresses:

AddressToId

IdToAddress

PubToID

Operations with variable values:

DecodeBase64

FormatMoney

Hash

EncodeBase64

Random

Sha256

Float

Int

Str

HexToBytes

Arithmetic operations:

Floor

Log10

Round

Log

Pow

Sqrt

Operations with JSON:

JSONEncode

JSONEncodeIndent

JSONDecode

Operations with strings:

HasPrefix

Size

ToLower

Contains

Sprintf

ToUpper

Replace

Substr

TrimSpace

Operations with bytes:

StringToBytes

BytesToString

Operations with date and time in SQL format:

BlockTime

DateTime

UnixDateTime

Operations with platform parameters:

HTTPRequest

HTTPPostJSON

Functions for master CLB nodes:

CreateOBS

RunOBS

RemoveOBS

GetOBSList

StopOBS

Needle functions reference

AppParam

Returns the value of a specified application parameter (from the application parameter table app_params).

Syntax

AppParam(app int, name string, ecosystemid int) string

  • App

    Application ID.

  • name Application parameter name.

  • Ecosystemid

    Ecosystem ID.

Example

AppParam(1, "app_account", 1)

DBFind

Queries data from a specified table with the specified parameters and returns an array array consisting of an array of objects map.

.Row() can get the first map element in the query, .One(column string) can get the first map element of a specified column in the query.

Syntax

DBFind(table string)
 [.Columns(columns array|string)]
 [.Where(where map)]
 [.WhereId(id int)]
 [.Order(order string)]
 [.Limit(limit int)]
 [.Offset(offset int)]
 [.Row()]
 [.One(column string)]
 [.Ecosystem(ecosystemid int)] array

  • table Table name.

  • сolumns Returns a list of columns. If not specified, all columns will be returned. The value is an array or a string separated by commas.

  • where Query conditions. Example: .Where({name: "John"}) or .Where({"id": {"$gte": 4}}). This parameter must contain an array of objects with search criteria. The array can contain nested elements. Following syntactic constructions are used:

    • {"field1": "value1", "field2": "value2"} Equivalent to field1 = "value1" AND field2 = "value2".

    • {"field1": {"$eq":"value"}} Equivalent to field = "value".

    • {"field1": {"$neq": "value"}} Equivalent to field != "value".

    • {"field1: {"$in": [1,2,3]} Equivalent to field IN (1,2,3).

    • {"field1": {"$nin": [1,2,3]} Equivalent to field NOT IN (1,2,3).

    • {"field": {"$lt": 12}} Equivalent to field <12.

    • {"field": {"$lte": 12}} Equivalent to field <= 12.

    • {"field": {"$gt": 12}} Equivalent to field> 12.

    • {"field": {"$gte": 12}} Equivalent to field >= 12.

    • {"$and": [<expr1>, <expr2>, <expr3>]} Equivalent to expr1 AND expr2 AND expr3.

    • {"$or": [<expr1>, <expr2>, <expr3>]} Equivalent to expr1 OR expr2 OR expr3.

    • {field: {"$like": "value"}} Equivalent to field like'%value%' (fuzzy search).

    • {field: {"$begin": "value"}} Equivalent to field like'value%' (starts with value).

    • {field: {"$end": "value"}} Equivalent to field like'%value' (ends with value).

    • {field: "$isnull"} Equivalent to field is null.

Make sure not to overwrite the keys of object arrays. For example, if you want to query with id>2 and id<5, you cannot use {id:{"$gt": 2}, id:{"$lt": 5}}, because the first element will be overwritten by the second element. You should use the following query structure: {id: [{"$gt": 2}, {"$lt": 5}]} {"$and": [{id:{"$gt": 2}}, {id:{"$lt": 5}}]}

  • Id Queries by ID. For example, .WhereId(1).

  • Order

    Used to sort the result set by a specified column, or by id by default.

    If you use only one field for sorting, you can specify it as a string. To sort multiple fields, you need to specify an array of string objects:

    Descending order: {"field": "-1"} Equivalent to field desc.

    Ascending order: {"field": "1"} Equivalent to field asc.

  • limit

    Returns the number of entries. 25, by default. The maximum number is 10,000.

  • Offset

    Offset.

  • Ecosystemid

    Ecosystem ID. By default, the table of the current ecosystem is queried.

Example

     var i int
     var ret string
     ret \= DBFind("contracts").Columns("id,value").Where({id: [{"$gt": 2}, {"$lt": 5}]}).Order( "id")
     while i <Len(ret) {
      var vals map
      vals \= ret[0]
      Println(vals["value"])
      i \= i + 1
     }
     ret \= DBFind("contracts").Columns("id,value").WhereId(10).One("value")
     if ret != nil {
      Println(ret)
      Println(ret)
      Println(ret)
     }

​

DBRow

Queries data from a specified table with the specified parameters. Returns an array array consisting of an array of objects map.

Syntax

DBRow(table string)
 [.Columns(columns array|string)]
 [.Where(where map)]
 [.WhereId(id int)]
 [.Order(order array|string)]
 [.Ecosystem(ecosystemid int)] map

  • table Table name. columns Returns a list of columns. If not specified, all columns will be returned. The value is an array or a string separated by commas.

  • where Query conditions. For example: .Where({name: "John"}) or .Where({"id": {"$gte": 4}}). For more details, see DBFind.

  • Id Query by ID. For example, .WhereId(1).

  • Order Used to sort the result set by a specified column, or by id by default. For more details, see DBFind.

  • Ecosystemid Ecosystem ID. By default, the table of the current ecosystem is queried.

Example

var ret map
ret = DBRow("contracts").Columns(["id","value"]).Where({id: 1})
Println(ret)

DBSelectMetrics

Returns the aggregated data of a metric. The metrics are updated each time 100 blocks are generated. And the aggregated data is stored on a 1-day cycle.

Syntax

DBSelectMetrics(metric string, timeInterval string, aggregateFunc string) array

  • metric Metric name

    • ecosystem_pages Number of ecosystem pages. Return value: key - ecosystem ID, value - number of ecosystem pages.

    • ecosystem_members Number of ecosystem members. Return value: key - ecosystem ID, value - number of ecosystem members.

    • ecosystem_tx Number of ecosystem transactions. Return value: key - ecosystem ID, value - number of ecosystem transactions.

  • timeInterval The time interval for aggregating metric data. For example: 1 day, 30 days.

  • aggregateFunc Aggregate function. For example, max, min, avg.

Example

var rows array
rows \= DBSelectMetrics("ecosystem_tx", "30 days", "avg")
var i int
while(i <Len(rows)) {
 var row map
 row \= rows[i]
 i \= i + 1
}

EcosysParam

Returns the value of a specified parameter in the ecosystem parameters table parameters.

Syntax

EcosysParam(name string) string

  • name Parameter name.

Example

Println(EcosysParam("founder_account"))

GetHistory

Returns the history of changes to entries in a specified table.

Syntax

GetHistory(table string, id int) array

  • table Table name.

  • Id Entry ID.

  • Return value Returns an array of objects of type map, which specify the history of changes to entries in tables. Each array contains the fields of a record before making the next change. The array is sorted by order of most recent changes. The id field in the array points to the id of the rollback_tx table. block_id represents the block ID, while block_time represents the block generation timestamp.

Example

var list array
var item map
list \= GetHistory("blocks", 1)
if Len(list) > 0 {
 item \= list[0]
}

GetHistoryRow

Returns a single snapshot from the change history of a specified entry in a specified table.

Syntax

GetHistoryRow(table string, id int, rollbackId int) map

  • table Table name.

  • Id Entry ID.

  • rollbackId rollback_tx The entry ID of the table.

  $result = GetHistoryRow("contracts",205,2358)

GetColumnType

Returns the data type of a specified field in a specified table.

Syntax

GetColumnType(table, column string) string

  • table Table name.

  • column Field Name.

  • Return value The following types can be returned: text, varchar, number, money, double, bytes, json, datetime, double.

Example

var coltype string
coltype \= GetColumnType("members", "member_name")

GetDataFromXLSX

Returns data from XLSX spreadsheets.

Syntax

GetDataFromXLSX(binId int, line int, count int, sheet int) string

  • binId ID in XLSX format in the binary table binary.

  • line The starting line number, starting from 0 by default.

  • count The number of rows that need to be returned.

  • sheet List number, starting from 1 by default.

Example

var a array
a \= GetDataFromXLSX(3, 12, 10, 1)

GetRowsCountXLSX

Returns the number of lines in a specified XLSX file.

Syntax

GetRowsCountXLSX(binId int, sheet int) int

  • binId ID in XLSX format in the binary table binary.

  • sheet List number, starting from 1 by default.

Example

var count int
count \= GetRowsCountXLSX(binid, 1)

LangRes

Returns a multilingual resource with name label for language lang, specified as a two-character code, for example: en, zh. If there is no language for a selected language, then the language resource of the en label is returned.

Syntax

LangRes(label string, lang string) string

  • label Language resource name.

  • lang Two-character language code.

Example

warning LangRes("@1confirm", "en")
error LangRes("@1problems", "zh")

GetBlock

Returns relevant information about a specified block.

Syntax

GetBlock(blockID int64) map

  • blockID Block ID.

  • Return value Return an array of objects:

    • id Block ID.

    • time Block generation timestamp.

    • key_id The account address of the verification node generated the block.

Example

var b map
b \= GetBlock(1)
Println(b)

DBInsert

Adds an entry to a specified table and return the entry ID.

Syntax

DBInsert(table string, params map) int

  • tblname Table name.

  • params An array of objects where keys are field names and values are inserted values.

Example

DBInsert("mytable", {name: "John Smith", amount: 100})

DBUpdate

Changes the column value of a specified entry ID in a specified table. If the entry ID does not exist in the table, an error is returned.

Syntax

DBUpdate(tblname string, id int, params map)

  • tblname Table name.

  • Id Entry ID.

  • params An array of objects where keys are field names and values are new values after changes.

Example

DBUpdate("mytable", myid, {name: "John Smith", amount: 100})

DBUpdateExt

Changes the value of a column in a specified table that matches the query condition.

Syntax

DBUpdateExt(tblname string, where map, params map)

  • tblname Table name.

  • where Query conditions. For more details, see DBFind.

  • params An array of objects where keys are field names and values are new values after changes.

Example

DBUpdateExt("mytable", {id: $key_id, ecosystem: $ecosystem_id}, {name: "John Smith", amount: 100})

DelColumn

Deletes a field in a specified table that has no records.

Syntax

DelColumn(tblname string, column string)

  • tblname Table name.

  • column The field to be deleted.

  DelColumn("mytable", "mycolumn")

DelTable

Deletes a specified table that has e no records.

Syntax

DelTable(tblname string)

  • tblname Table name.

Example

DelTable("mytable")

Append

Inserts any type of val into the src array.

Syntax

Append(src array, val anyType) array

  • src The original array.

  • val The value to be inserted.

Example

var list array
list \= Append(list, "new_val")

Join

Combines elements of the in array into a string with a specified sep separator.

Syntax

Join(in array, sep string) string

  • In Array name.

  • sep Separator.

Example

 var val string, myarr array
 myarr[0] \= "first"
 myarr[1] \= 10
 val \= Join(myarr, ",")

Split

Uses the sep separator to split the in string into elements and put them into an array.

Syntax

 Split(in string, sep string) array

  • In String.

  • sep Separator.

Example

var myarr array
myarr \= Split("first,second,third", ",")

Len

Returns the number of elements in a specified array.

Syntax

Len(val array) int

  • val Array.

Example

 if Len(mylist) \== 0 {
  ...
 }

Row

The list parameter must not be specified in this case. Return the first object array in the array list. If the list is empty, an empty result is returned. This function is mostly used in conjunction with the DBFind function. When using this function, you cannot specify parameters.

Syntax

 Row(list array) map

  • list The array of objects returned by the DBFind function.

Example

 var ret map
 ret \= DBFind("contracts").Columns("id,value").WhereId(10).Row()
 Println(ret)

One

Returns the field value of the first object array in the array list. If the list array is empty, nil is returned. It is mostly used in conjunction with the DBFind function. When using this function, you cannot specify parameters.

Syntax

 One(list array, column string) string

  • list

The array of objects returned by the DBFind function.

  • column

    Field Name.

Example

  var ret string
  ret \= DBFind("contracts").Columns("id,value").WhereId(10).One("value")
  if ret != nil {
   Println(ret)
  }

GetMapKeys

Returns the key array in the object array.

Syntax

 GetMapKeys(val map) array

  • val Object array.

Example

  var val map
  var arr array
  val["k1"] \= "v1"
  val["k2"] \= "v2"
  arr \= GetMapKeys(val)

SortedKeys

Returns a sorted key array in the object array.

Syntax

  SortedKeys(val map) array

  • val Object array.

Example

  var val map
  var arr array
  val["k2"] \= "v2"
  val["k1"] \= "v1"
  arr \= SortedKeys(val)

CallContract

Calls the contract with a specified name. All parameters of the data section in the contract must be included in an object array. This function returns the value assigned to the $result variable by a specified contract.

Syntax

  CallContract(name string, params map)

  • name The name of the contract being called.

  • params An associative array of the contract input data.

Example

  var par map
  par["Name"] \= "My Name"
  CallContract("MyContract", par)

ContractAccess

Checks if the name of contract being executed matches one of the names listed in the parameters. Usually it is used to control contract access to tables. When editing table fields or inserting and adding new column fields in the permissions section of the table, please specify this function in the permissions fields.

Syntax

ContractAccess(name string, [name string]) bool

  • name Contract name.

Example

  ContractAccess("MyContract")
  ContractAccess("MyContract","SimpleContract")

ContractConditions

Calls the conditions section in the contract with a specified name. For this type of contracts, the data section must be empty. If the conditions section is executed without error, it returns true. If there is an error during execution, the parent contract will also be terminated due to the error. This function is usually used to control the contract's access to tables and can be called in the permission fields when editing system tables.

Syntax

  ContractConditions(name string, [name string]) bool

  • name Contract name.

Example

  ContractConditions("MainCondition")

EvalCondition

Gets the value of the condfield field in the record with a 'name' field from the tablename table, and checks the conditions of the condfield field value.

Syntax

  EvalCondition(tablename string, name string, condfield string)

  • tablename Table name.

  • name Queries the value with the 'name' field.

  • condfield The name of the field whose conditions needs to be checked.

Example

  EvalCondition(`menu`, $Name, `conditions`)

GetContractById

Returns its contract name by contract ID. If not found the contract, an empty string is returned.

Syntax

  GetContractById(id int) string

  • Id The contract ID in the contract table contracts.

Example

  var name string
  name = GetContractById($IdContract)

GetContractByName

This function returns its contract ID by contract name. If not found the contract, zero is returned.

Syntax

  GetContractByName(name string) int

  • name The contract name in the contract table contracts.

Example

  var id int
  id = GetContractByName(`NewBlock`)

RoleAccess

Checks whether the role ID of the contract caller matches one of the IDs specified in the parameter. You can use this function to control contract access to tables and other data.

Syntax

 RoleAccess(id int, [id int]) bool

  • Id Role ID.

Example

  RoleAccess(1)
  RoleAccess(1, 3)

TransactionInfo

Queries transactions by specified hash value and returns information about the contract executed and its parameters.

Syntax

  TransactionInfo(hash: string)

  • hash Transaction hash in hexadecimal string format.

  • Return value This function returns a string in JSON format:

    {"contract":"ContractName", "params":{"key": "val"}, "block": "N"}

  • contract Contract name.

  • params Data passed to contract parameters. block ID of the block that processed the transaction.

Example

  var out map
  out \= JSONDecode(TransactionInfo(hash))

Throw

Generates an error of type exception.

Syntax

Throw(ErrorId string, ErrDescription string)

  • ErrorId Error identifier.

  • ErrDescription Error description.

  • Return value The format of this type of transaction results:

    {"type":"exception","error":"Error description","id":"Error ID"}

Example

Throw("Problem", "There is a problem")

ValidateCondition

Tries to compile the conditions specified by the condition parameter. If there is an error during the compilation process, an error is generated and the contract called is terminated. This function is designed to check the correctness of the conditional format.

Syntax

  ValidateCondition(condition string, state int)

  • condition The conditional format that needs to be verified.

  • state Ecosystem ID. If you check the global condition, please specify it as 0.

Example

  ValidateCondition(`ContractAccess("@1MyContract")`, 1)

AddressToId

Returns the corresponding account address by wallet address. If an invalid address is specified, '0' is returned.

Syntax

  AddressToId(address string) int

  • Address Wallet address in XXXX-...-XXXX format or number format.

Example

  wallet = AddressToId($Recipient)

IdToAddress

Returns the corresponding wallet address by account address. If an invalid address is specified, the invalid address 'invalid' is returned.

Syntax

  IdToAddress(id int) string

  • Id Account address.

Example

  $address = IdToAddress($id)

PubToID

The account address is returned by public key in hexadecimal format.

Syntax

  PubToID(hexkey string) int

  • hexkey The public key in hexadecimal format.

Example

var wallet int
  wallet \= PubToID("04fa5e78.....34abd6")

DecodeBase64

Returns a string by specifying the base64 format

Syntax

  DecodeBase64(input string) string

  • Input String in base64 format.

Example

  val \= DecodeBase64(mybase64)

EncodeBase64

Returns a string in base64 format by specifying a string.

Syntax

  EncodeBase64(input string) string

  • Input The string to be encoded.

Example

 var base64str string
  base64str \= EncodeBase64("my text")

Float

Converts an integer or string to a float number.

Syntax

  Float(val int|string) float

  • val An integer or string.

Example

  val \= Float("567.989") + Float(232)

HexToBytes

Converts a string in hexadecimal format to byte type bytes.

Syntax

  HexToBytes(hexdata string) bytes

  • hexdata A string in hexadecimal format.

Example

  var val bytes
  val \= HexToBytes("34fe4501a4d80094")

FormatMoney

Returns the string value of exp / 10 ^ digit.

Syntax

FormatMoney(exp string, digit int) string

  • Exp A number in string format. digit The exponent (positive or negative) of 10 in the expression Exp/10^digit. Positive values determine decimal places.

Example

  s \= FormatMoney("78236475917384", 0)

Random

Returns a random number between min and max (min <= result <max). Both min and max must be positive numbers.

Syntax

 Random(min int, max int) int

  • min The minimum value among random numbers.

  • max The upper limit of random numbers. The random number generated will be less than this value.

Example

  i \= Random(10,5000)

Int

Converts a value in string format to an integer.

Syntax

  Int(val string) int

  • val A number in string format.

Example

  mystr \= "-37763499007332"
  val \= Int(mystr)

Hash

Returns the hash of a specified byte array or string, which is generated by the system encryption library crypto.

Syntax

 Hash(val interface{}) string, error

  • val A string or byte array.

Example

  var hash string
  hash \= Hash("Test message")

Sha256

Returns the SHA256 hash of a specified string.

Syntax

 Sha256(val string) string

  • val A string requires the Sha256 hash operation.

Example

  var sha string
  sha \= Sha256("Test message")

Str

Converts an integer int or float float number to a string.

Syntax

Str(val int|float) string

  • val An integer or float number.

Example

  myfloat \= 5.678
  val \= Str(myfloat)

JSONEncode

Converts a number, string or array to a string in JSON format.

Syntax

  JSONEncode(src int|float|string|map|array) string

  • src Data to convert.

Example

var mydata map
  mydata["key"] \= 1
  var json string
  json \= JSONEncode(mydata)

JSONEncodeIndent

Uses the specified indentation to convert a number, string, or array to a string in JSON format.

Syntax

  JSONEncodeIndent(src int|float|string|map|array, indent string) string

  • src Data to convert.

  • Indent The string will be used as indentation.

Example

var mydata map
  mydata["key"] \= 1
  var json string
  json \= JSONEncodeIndent(mydata, "\t")

JSONDecode

Converts a string in JSON format to a number, string or array.

Syntax

  JSONDecode(src string) int|float|string|map|array

  • src A string containing data in JSON format.

Example

  var mydata map
  mydata = JSONDecode(`{"name": "John Smith", "company": "Smith's company"}`)

HasPrefix

Checks whether the string starts with a specified string.

Syntax

HasPrefix(s string, prefix string) bool

  • s A string.

  • prefix The prefix to check.

  • Return value If the string starts with a specified string, true is returned.

Example

  if HasPrefix($Name, `my`) {
  ...
  }

Contains

Checks whether the string contains a specified substring.

Syntax

 Contains(s string, substr string) bool

  • s A string.

  • substr A substring.

  • Return value If the string contains the substring, it returns true.

Example

  if Contains($Name, `my`) {
  ...
  }

Replace

Replaces old (the old string) with new (the new string) in the string.

Syntax

  Replace(s string, old string, new string) string

  • s The original string.

  • Old The substring to replace.

  • new The new string.

Example

  s = Replace($Name, `me`, `you`)

Size

Returns the number of bytes in a specified string.

Syntax

  Size(val string) int

  • val A string.

Example

  var len int
  len = Size($Name)

Sprintf

This function creates a string using the specified template and parameters. Available wildcards:

  • %d (integer)

  • %s (string)

  • %f (float)

  • %v (any type)

Syntax

  Sprintf(pattern string, val ...) string

  • pattern A string template.

Example

  out \= Sprintf("%s\=%d", mypar, 6448)

Substr

Returns the substring obtained from a specified string starting from the offset offset (calculated from 0 by default), and the maximum length is limited to length. If the offset or length is less than zero, or the offset is greater than the length, an empty string is returned. If the sum of the offset and length is greater than the string size, then, the substring will be returned starting from the offset to the end of the string.

Syntax

  Substr(s string, offset int, length int) string

  • val A string.

  • Offset Offset.

  • length Length of the substring.

Example

  var s string
  s = Substr($Name, 1, 10)

ToLower

Returns a specified string in lowercase.

Syntax

  ToLower(val string) string

  • val A string.

Example

  val \= ToLower(val)

ToUpper

Returns a specified string in uppercase.

Syntax

  ToUpper(val string) string

  • val A string.

Example

  val \= ToUpper(val)

TrimSpace

Deletes the leading and trailing spaces, tabs and newlines of a specified string.

Syntax

  TrimSpace(val string) string

  • val A string.

Example

var val string
val \= TrimSpace(" mystr ")

Floor

Returns the largest integer value less than or equal to a specified number, float number, and string.

Syntax

  Floor(x float|int|string) int

  • x A number, float number, and string.

Example

val \= Floor(5.6) // returns 5

Log

Returns the natural logarithm of a specified number, float number, and string.

Syntax

  Log(x float|int|string) float

  • x A number, float number, and string.

Example

  val \= Log(10)

Log10

Returns the base-10 logarithm of a specified number, float number, and string.

Syntax

  Log10(x float|int|string) float

  • x A number, float number, and string.

Example

 val \= Log10(100)

Pow

Returns the specified base to the specified power (xy).

Syntax

  Pow(x float|int|string, y float|int|string) float

  • x Base number.

  • y Exponent.

Example

  val \= Pow(2, 3)

Round

Returns the value of a specified number rounded to the nearest integer.

Syntax

  Round(x float|int|string) int

  • x A number.

Example

  val \= Round(5.6)

Sqrt

Returns the square root of a specified number.

  Sqrt(x float|int|string) float

  • x A number.

Example

  val \= Sqrt(225)

StringToBytes

Converts a string to bytes.

Syntax

  StringToBytes(src string) bytes

  • src A string.

Example

 var b bytes
  b \= StringToBytes("my string")

BytesToString

Converts bytes to string.

Syntax

  BytesToString(src bytes) string

  • src Byte.

Example

  var s string
  s = BytesToString($Bytes)

SysParamString

Returns the value of a specified platform parameter.

Syntax

  SysParamString(name string) string

  • name Parameter name.

Example

  url = SysParamString(`blockchain_url`)

SysParamInt

Returns the value of a specified platform parameter in the form of a number.

Syntax

  SysParamInt(name string) int

  • name Parameter name.

Example

  maxcol = SysParam(`max_columns`)

DBUpdateSysParam

Updates the value and conditions of a platform parameter. If you do not need to change the value or conditions, please specify an empty string in the corresponding parameter.

Syntax

  DBUpdateSysParam(name, value, conditions string)

  • name Parameter name.

  • value New value of a parameter.

  • conditions New conditions for updating a parameter.

Example

  DBUpdateSysParam(`fuel_rate`, `400000000000`, ``)

UpdateNotifications

Obtains the notification list of a specified key from the database, and sends the notification obtained to Centrifugo.

Syntax

  UpdateNotifications(ecosystemID int, keys int...)

  • EcosystemID Ecosystem ID.

  • key A list of account addresses, separated by commas. Or you can use an array to specify a list of account addresses.

Example

  UpdateNotifications($ecosystem_id, $key_id, 23345355454, 35545454554)
  UpdateNotifications(1, [$key_id, 23345355454, 35545454554])

UpdateRolesNotifications

Obtains the notification list of all account addresses of a specified role ID in the database, and sends the notification obtained to Centrifugo.

Syntax

  UpdateRolesNotifications(ecosystemID int, roles int ...)

  • EcosystemID Ecosystem ID.

  • roles A list of role IDs, separated by commas. Or you can use an array to specify a list of role IDs.

Example

  UpdateRolesNotifications(1, 1, 2)

HTTPRequest

Sends HTTP requests to the specified address. Note This function can only be used in CLB contracts.

Syntax

  HTTPRequest(url string, method string, heads map, pars map) string

  • Url Address, to which the request will be sent.

  • method Request type (GET or POST).

  • heads An array of request headers, objects.

  • pars Request parameters.

Example

  var ret string
   var ret string
  var ret string
  var pars, heads, json map
  heads["Authorization"] = "Bearer "+ $auth_token
  pars["obs"] = "true"
  ret = HTTPRequest("http://localhost:7079/api/v2/content/page/default_page", "POST", heads, pars)
  json = JSONToMap(ret)

HTTPPostJSON

This function is similar to the HTTPRequest function, but it sends a POST request and the request parameters are strings.

Note This function can only be used in CLB contracts

Syntax

  HTTPPostJSON(url string, heads map, pars string) string

  • Url Address, to which the request will be sent.

  • heads An array of request headers, objects.

  • pars Request parameters as a JSON string.

Example

  var ret string
   var ret string
  var ret string
  var heads, json map
  heads["Authorization"] = "Bearer "+ $auth_token
  ret = HTTPPostJSON("http://localhost:7079/api/v2/content/page/default_page", heads, `{"obs":"true"}`)
  json = JSONToMap(ret)

BlockTime

Returns the generation time of the block in SQL format.

Syntax

  BlockTime()

Example

  var mytime string
  mytime \= BlockTime()
  DBInsert("mytable", myid, {time: mytime})

DateTime

Converts the timestamp unixtime to a string in YYYY-MM-DD HH:MI:SS format.

Syntax

  DateTime(unixtime int) string

Example

  DateTime(1532325250)

UnixDateTime

Converts a string in YYYY-MM-DD HH:MI:SS format to a timestamp unixtime

Syntax

  UnixDateTime(datetime string) int

Example

  UnixDateTime("2018-07-20 14:23:10")

CreateOBS

Creates a child CLB. This function can only be used in the master CLB mode.

Syntax

  CreateOBS(OBSName string, DBUser string, DBPassword string, OBSAPIPort int)

  • OBSName CLB name.

  • DBUser The role name of the database.

  • DBPassword The password of the role.

  • OBSAPIPort The port of the API request.

Example

  CreateOBS("obsname", "obsuser", "obspwd", 8095)

GetOBSList

Returns the list of child CLBs. This function can only be used in the master CLB mode.

Syntax

  GetOBSList()

  • Return value An array of objects, where the key is the CLB name and the value is the process state.

RunOBS

A process running the CLB. This function can only be used in the master CLB mode.

Syntax

  RunOBS(OBSName string)

  • OBSName CLB name.

    It can only contain letters and numbers, and the space symbol cannot be used.

StopOBS

Stop the process of a specified CLB. This function can only be used in the master CLB mode.

Syntax

  StopOBS(OBSName string)

  • OBSName CLB name.

It can only contain letters and numbers, and the space symbol cannot be used.

RemoveOBS

Deletes the process of a specified CLB. This function can only be used in the master CLB mode.

Syntax

  RemoveOBS(OBSName string)

  • OBSName CLB name.

It can only contain letters and numbers, and the space symbol cannot be used.

System Contracts

System contracts are created by default when the IBax blockchain platform is launched. All these contracts were created in the first ecosystem. This is why you need to specify their full names when calling them from other ecosystems, for example, @1NewContract.

NewEcosystem

This contract creates a new ecosystem. To obtain the ID of the ecosystem created, you must quote the result filed returned in txstatus. Parameters:

  • Name string - name of the ecosystem. It can be changed later.

EditEcosystemName

Changes the name of the ecosystem in the 1_ecosystems table that only exists in the first ecosystem. Parameters:

  • EcosystemID int - changes the name of the ecosystem ID;

  • NewName string - new name of the ecosystem.

NewContract

Creates a new contract in the current ecosystem. Parameters:

  • ApplicationId int - the application to which a new contract belongs;

  • Value string - contract source code. The upper layer must have only one contract;

  • Conditions string - changes the conditions of the contract;

  • TokenEcosystem int "optional" - ecosystem ID. It determines which token will be used for transactions when the contract is activated.

EditContract

Edits the contract in the current ecosystem. Parameters:

  • Id int - the contract ID changed;

  • Value string "optional" - source code of the contract;

  • Conditions string "optional" - changes the conditions of the contract.

BindWallet

Binding the contract to the wallet address in the current ecosystem. After binding with the contract, the contract execution fee will be paid under this address. Parameters:

  • Id int - the contract ID to be bound.

  • WalletId string "optional" - the wallet address bound to the contract.

UnbindWallet

Unbinding the contract from the wallet address in the current ecosystem. Only addresses bound to the contract can be unbound. After unbinding the contract, users who execute the contract will pay the execution fee. Parameters:

  • Id int - the ID of the contract being bound.

NewParameter

A new ecosystem parameter has been added to the current ecosystem. Parameters:

  • Name string - parameter name;

  • Value string - parameter value;

  • Conditions string - conditions to change the parameter.

EditParameter

Changes existing ecosystem parameters in the current ecosystem. Parameters:

  • Name string - name of the parameter to be changed;

  • Value string - new parameter value;

  • Conditions string - new conditions to change the parameter.

NewMenu

Adds a new menu in the current ecosystem. Parameters:

  • Name string - menu name;

  • Value string - menu source code;

  • Title string "optional" - menu title;

  • Conditions string - conditions to change the menu.

EditMenu

Changes the existing menu in the current ecosystem. Parameters:

  • Id int - menu ID to be changed;

  • Value string "optional" - source code of the new menu;

  • Title string "optional" - title of the new menu;

  • Conditions string "optional" - new conditions to change the menu.

AppendMenu

Adds the source code content to existing menus in the current ecosystem Parameters:

  • Id int - menu ID;

  • Value string - source code to be added.

NewPage

Adds a new page in the current ecosystem. Parameters:

  • Name string - name of the page;

  • Value string - source code of the page;

  • Menu string - name of the menu associated with the page;

  • Conditions string - conditions to change the page;

  • ValidateCount int "optional" - number of nodes required for page validation. If this parameter is not specified, the min_page_validate_count ecosystem parameter value is used. The value of this parameter cannot be less than min_page_validate_count and greater than max_page_validate_count;

  • ValidateMode int "optional" - mode of page validity check. The page will be checked when it is loaded if the value of this parameter is 0; or checked when it is loaded or exit the page if the value of this parameter is 1.

EditPage

Changes existing pages in the current ecosystem. Parameters:

  • Id int - ID of the page to be changed;

  • Value string "optional" - source code of the new page;

  • Menu string "optional" - name of the new menu associated with the page;

  • Conditions string "optional" - new conditions to change the page;

  • ValidateCount int "optional" - number of nodes required for page validation. If this parameter is not specified, the min_page_validate_count ecosystem parameter value is used. The value of this parameter cannot be less than min_page_validate_count and greater than max_page_validate_count;

  • ValidateMode int "optional" - mode of page validity check. The page will be checked when it is loaded if the value of this parameter is 0; or checked when it is loaded or exit the page if the value of this parameter is 1.

AppendPage

Adds the source content to existing pages in the current ecosystem. Parameters:

  • Id int - ID of the page to be changed;

  • Value string - the source code to be added.

NewBlock

Adds a page module to the current ecosystem. Parameters:

  • Name string - name of the module;

  • Value string - source code of the module;

  • Conditions string - conditions to change the module.

EditBlock

Changes existing page modules in the current ecosystem. Parameters:

  • Id int - module ID to be changed;

  • Value string - source code of the new module;

  • Conditions string - new conditions to change the module.

NewTable

Adds a new table to the current ecosystem. Parameters:

  • ApplicationId int - application ID of the associated table;

  • Name string - name of the new table;

  • Columns string - field array in JSON format [{"name":"...", "type":"...","index": "0", "conditions":".. ."},...], where –name - field name, only Latin characters; –type - data type varchar,bytea,number,datetime,money,text,double,character; –index - non-primary key field 0, primary key 1; –conditions - conditions to change the field data, and the access permissions must be specified in JSON format "{"update":"ContractConditions(MainCondition)", "read":"ContractConditions(MainCondition)"} ``;

  • Permissions string - access permissions in JSON format {"insert": "...", "new_column": "...", "update": "...", "read": ".. ."}. –insert - permission to insert entries; –new_column - permission to add a new column; –update - permission to change entry data; –read - permission to read entry data.

EditTable

Changes the access permissions of a table in the current ecosystem. Parameters:

  • Name string - name of the table;

  • InsertPerm string - permission to insert entries into the table;

  • UpdatePerm string - permission to update entries in the table;

  • ReadPerm string - permission to read entries in the table;

  • NewColumnPerm string - permission to create a new column;

NewColumn

Adds a new field to the table of the current ecosystem. Parameters:

  • TableName string - table name;

  • Name string - field name in Latin characters;

  • Type string - data type varchar,bytea,number,money,datetime,text,double,character;

  • UpdatePerm string - permission to change the value in the column;

  • ReadPerm string - permission to read the value in the column.

EditColumn

Changes the permission of a specified table field in the current ecosystem. Parameters:

  • TableName string - table name;

  • Name string - field name in Latin characters to be changed;

  • UpdatePerm string - new permission to change the value in the column;

  • ReadPerm string - new permission to read the value in the column.

NewLang

Adds language resources to the current ecosystem, and the permission to do so is set in the changing_language parameter of the ecosystem parameters.

Parameters:

  • Name string - name of the language resources in Latin characters;

  • Trans string - string in JSON format, with a two-character lang code as the key and the translated string as the value. For example, {"en": "English text", "zh": "Chinese text"}.

EditLang

Changes the language resources in the current ecosystem, and the permission to do so is set in the changing_language parameter of the ecosystem parameter.

Parameters:

  • Id int - language resources ID.

  • Trans - string in JSON format, with a two-character lang code as the key and the translated string as the value. For example, {"en": "English text", "zh": "Chinese text"}.

Import

Imports an application into the current ecosystem and imports the data loaded from the ImportUpload contract.

Parameters:

  • Data string - data imported in text format, which comes from a file exported by the ecosystem.

ImportUpload

Loads an external application file into the buffer_data table of the current ecosystem for subsequent import.

Parameters:

  • InputFile file - a file written to the buffer_data table of the current ecosystem.

NewAppParam

Adds new application parameters to the current ecosystem.

Parameters:

  • ApplicationId int - application ID;

  • Name string - parameter name;

  • Value string - parameter value;

  • Conditions string - permission to change the parameter.

EditAppParam

Changes existing application parameters in the current ecosystem.

Parameters:

  • Id int - application parameter ID;

  • Value string "optional" - new parameter value;

  • Conditions string "optional" - new permissions to change the parameter.

NewDelayedContract

Adds a new task to the delayed contracts scheduler daemon.

The delayered contracts scheduler runs contracts required by the currently generated block.

Parameters:

  • Contract string - contract name;

  • EveryBlock int - the contract will be executed every such amount of blocks;

  • Conditions string - permission to change the task;

  • BlockID int "optional" - the block ID where the contract must be executed. If not specified, it will be calculated automatically by adding the "current block ID" + EveryBlock;

  • Limit int "optional" - the maximum number of task execution. If not specified, the task will be executed for an unlimited times.

EditDelayedContract

Changes a task in the delayed contracts scheduler daemon.

Parameters:

  • Id int - task ID;

  • Contract string - contract name;

  • EveryBlock int - the contract will be executed every such amount of blocks;

  • Conditions string - permission to change the task;

  • BlockID int "optional" - the block ID where the contract must be executed. If not specified, it will be calculated automatically by adding the "current block ID" + EveryBlock;

  • Limit int "optional" - the maximum number of task execution. If not specified, the task will be executed for an unlimited times.

  • Deleted int "optional" - task switching. A value of 1 will disable the task. A value of 0 will enable the task.

UploadBinary

Adds or overwrites a static file in the X_binaries table. When calling a contract via HTTP API, the request must be in multipart/form-data format; the DataMimeType parameter will be used in conjunction with the form data.

Parameters:

  • Name string - name of the static file;

  • Data bytes - content of the static file;

  • DataMimeType string "optional" - a static file in mime-type format;

  • ApplicationId int - the application ID associated with the X_binaries table. If the DataMimeType parameter is not passed, the application/octet-stream format is used by default.

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