Skip to main content
Version: 0.9

Introduction

The KCL language provides multiple general-purpose programming language interfaces, with identical API forms and features.

C/Rust APIs​

The core of KCL is developed in Rust, and the C language API is exported externally for packaging and integration in other high-level languages such as Go, Python, etc.

REST-API​

The C-API provided by KCL does not have a REST-API. The REST-API is defined by Protobuf.

Start REST Service​

The RestAPI service can be started in the following way:

kcl server

The service can then be requested via the POST protocol:

curl -X POST http://127.0.0.1:2021/api:protorpc/BuiltinService.Ping --data '{}'

The output is

{
  "error": "",
  "result": {}
}

The POST request and the returned JSON data are consistent with the structure defined by Protobuf.

BuiltinService​

Where the /api:protorpc/BuiltinService.Ping path represents the Ping method of the BuiltinService service.

The complete BuiltinService is defined by Protobuf:

service BuiltinService {
    rpc Ping(Ping_Args) returns(Ping_Result);
    rpc ListMethod(ListMethod_Args) returns(ListMethod_Result);
}

message Ping_Args {
    string value = 1;
}
message Ping_Result {
    string value = 1;
}

message ListMethod_Args {
    // empty
}
message ListMethod_Result {
    repeated string method_name_list = 1;
}

The Ping method can verify whether the service is normal, and the ListMethod method can query the list of all services and functions provided.

KclvmService​

The KclvmService service is a service related to KCL functionality. The usage is the same as the BuiltinService service.

For example, there is the following Person structure definition:

schema Person:
    key: str

    check:
        "value" in key  # 'key' is required and 'key' must contain "value"

Then we want to use Person to verify the following JSON data:

{ "key": "value" }

This can be done through the ValidateCode method of the KclvmService service. Refer to the ValidateCode_Args structure of the ValidateCode method:

message ValidateCode_Args {
    string data = 1;
    string code = 2;
    string schema = 3;
    string attribute_name = 4;
    string format = 5;
}

Construct the JSON data required by the POST request according to the ValidateCode_Args structure, which contains the Person definition and the JSON data to be verified:

{
  "code": "\nschema Person:\n    key: str\n\n    check:\n        \"value\" in key  # 'key' is required and 'key' must contain \"value\"\n",
  "data": "{\"key\": \"value\"}"
}

Save this JSON data to the vet-hello.json file and verify it with the following command:

$ curl -X POST \
    http://127.0.0.1:2021/api:protorpc/KclvmService.ValidateCode \
    -H  "accept: application/json" \
    --data @./vet-hello.json
{
    "error": "",
    "result": {
        "success": true
    }
}