从 Ballerina 资源函数返回记录

Question

请考虑以下芭蕾舞服务。

import ballerina/http;

public type Tool readonly & record {|
    string name;
    string api_path;
    ToolInput[] inputs;
|};

public type ToolInput readonly & record {|
    string name;
    boolean required;
    any default_value = ();
    any[] allowed_values = ["any"];
|};


public final table<Tool> key(name) toolsTable = table [
    {
        name: "deploy", 
        api_path: "deploy", 
        inputs: [
            {name: "environment", required: true},
            {name: "service", required: true},
            {name: "version", required: false, default_value: "master"},
            {name: "version_type", required: false, default_value: "branch", allowed_values: ["branch", "commit_id", "build_number"]}        
        ]
    }
];

service /foo on new http:Listener(9090) {

    resource function get list\-tools() returns Tool[] {
        return toolsTable.toArray();
    }   
}

当从资源函数返回

Tool[]

数组时，我们收到错误

invalid resource method return type: expected anydata|http:Response|http:StatusCodeResponse|error, but found Tool[]

。

从资源函数返回 Ballerina 记录时有哪些限制？

Answer 1

正如错误消息中提到的，我们只能返回属于

anydata

、

http:Response

、

http:StatusCodeResponse

或

error

之一的类型。根据上面的例子，返回类型

Tool[]

应该属于

anydata

但是

Tool

记录包含两个类型为

any

的字段。因此，

Tool[]

不属于

anydata

。我们只需将这些字段的类型更改为

anydata

，如下所示。

import ballerina/http;

public type Tool readonly & record {|
    string name;
    string api_path;
    ToolInput[] inputs;
|};

public type ToolInput readonly & record {|
    string name;
    boolean required;
    anydata default_value = ();
    anydata[] allowed_values = ["any"];
|};


public final table<Tool> key(name) toolsTable = table [
    {
        name: "deploy", 
        api_path: "deploy", 
        inputs: [
            {name: "environment", required: true},
            {name: "service", required: true},
            {name: "version", required: false, default_value: "master"},
            {name: "version_type", required: false, default_value: "branch", allowed_values: ["branch", "commit_id", "build_number"]}        
        ]
    }
];

service /foo on new http:Listener(9090) {

    resource function get list\-tools() returns Tool[] {
        return toolsTable.toArray();
    }   
}