NativeScript API Client

A NativeScript module for simply calling HTTP based APIs.

NativeScript Toolbox

This module is part of nativescript-toolbox.

License

MIT license

Platforms

• Android
• iOS

Installation

Run

tns plugin add nativescript-apiclient

inside your app project to install the module.

Demo

For quick start have a look at the plugin/index.ts or use the "IntelliSense" of your IDE to learn how it works.

Otherwise...

Usage

Import

import ApiClient = require("nativescript-apiclient");

Example

import ApiClient = require("nativescript-apiclient");
import HTTP = require("http");

interface IUser {
    displayName?: string;
    id?: number;
    name?: string;
}

var client = ApiClient.newClient({
    baseUrl: "https://api.example.com/users",
    route: "{id}",  
});

client.beforeSend(function(opts: HTTP.HttpRequestOptions, tag: any) {
                      console.log("Loading user: " + tag);
                      
                      // prepare the request here
                  })
      .clientError(function(result: ApiClient.IApiClientResult) {
                       // handle all responses with status code 400 to 499
                   })
      .serverError(function(result: ApiClient.IApiClientResult) {
                       // handle all responses with status code 500 to 599
                   })
      .success(function(result: ApiClient.IApiClientResult) {
                    // handle all responses with that were NOT
                    // handled by 'clientError()' and 'serverError()'
                    // 
                    // especially with status code less than 400 and greater than 599
                    
                    var user = result.getJSON<IUser>();
               })
      .error(function(err: ApiClient.IApiClientError) {
                 // handle API client errors
             })
      .completed(function(ctx: ApiClient.IApiClientCompleteContext) {
                     // invoked after "result" and "error" actions
                 });

var credentials = new ApiClient.BasicAuth("Marcel", "p@ssword!");

for (var userId = 1; userId <= 100; userId++) {
    // start a GET request
    // 
    // [GET]  https://api.example.com/users/{id}?ver=1.6.6.6
    client.get({
        authorizer: credentials,
    
        // request headers
        headers: {
            'X-MyHeader-TM': '5979',
            'X-MyHeader-MK': '23979'
        },
        
        // URL parameters
        params: {
            ver: '1.6.6.6'
        },
    
        // route parameters
        routeParams: {
            id: userId.toString()  // {id}
        },
        
        // global value for all callbacks 
        tag: userId
    });
}

Routes

Routes are suffixes for a base URL.

You can define one or parameters inside that route, which are replaced when you start a request.

If you create a client like this

var client = ApiClient.newClient({
    baseUrl: "https://api.example.com/users",
    route: "{id}/{resource}",  
});

and start a request like this

client.get({
    routeParams: {
        id: "5979",  // {id}
        resource: "profile"  // {resource}
    }
});

the client will call the URL

[GET]  https://api.example.com/users/5979/profile

Parameter values can also be functions, what means that the value that is returned by that functions is used as value:

var getUserId = function() : string {
    // load the user ID from somewhere
};

client.get({
    routeParams: {
        id: getUserId,  // {id}
        resource: "profile"  // {resource}
    }
});

A function must have the following structure:

function (paramName: string, routeParams: any, match: string, formatExpr: string, funcDepth: string) : any {
    return <THE-VALUE-TO-USE>;
}

Formatting values

Followed by a : char a route parameter definition can additionally contain a "format expression".

These expressions can help you to parse and format parameter values.

The first step to do this is to define a so called "format provider" callback in a client:

client.addFormatProvider((ctx : ApiClient.IFormatProvider) => {
    var toStringSafe = function() : string { 
        return ctx.value ? ctx.value.toString() : "";
    };

    if (ctx.expression === "upper") {    
        ctx.handled = true;
        return toStringSafe().toUpperCase();  // the new value
    }
    else if (ctx.expression === "number") {
        var n = parseInt(toStringSafe().trim());
        if (isNaN(n)) {
            throw "'" + ctx.value + "' is NOT a number!";
        }
        
        ctx.handled = true;
        return n.toString();
    }
});

Here we defined the two expressions upper (convert to upper case chars) and number (keep sure to have a valid number).

To use them you can define a route like this:

{id:number}/{resource:upper}

Now if you setup your client

var client = ApiClient.newClient({
    baseUrl: "https://api.example.com/users",
    route: "{id:number}/{resource:upper}",  
});

and start a request like this

client.get({
    routeParams: {
        id: "5979",
        resource: "profile"
    }
});

the client will call the URL

[GET]  https://api.example.com/users/5979/PROFILE

The ctx object in the format provider call of addFormatProvider() has the following structure:

interface IFormatProviderContext {
    /**
     * Gets the format expression.
     */
    expression: string;
    
    /**
     * Gets if the expression has been handled or not.
     */
    handled: boolean;
    
    /**
     * Gets the underlying (unhandled) value.
     */
    value: any;
}

Authorization

You can submit an optional IAuthorizer object when you start a request:

interface IAuthorizer {
    /**
     * Prepares a HTTP request for authorization.
     * 
     * @param {HTTP.HttpRequestOptions} reqOpts The request options.
     */
    prepare(reqOpts: HTTP.HttpRequestOptions);
}

The plugin provides the following implementations:

AggregateAuthorizer

var authorizer = new ApiClient.AggregateAuthorizer();
authorizer.addAuthorizers(new ApiClient.BasicAuth("Username", "Password"),
                          new ApiClient.BearerAuth("MySecretToken"));

BasicAuth

var authorizer = new ApiClient.BasicAuth("Username", "Password");

BearerAuth

var authorizer = new ApiClient.BearerAuth("MySecretToken");

OAuth

var authorizer = new ApiClient.OAuth("MySecretToken");
authorizer.setField('oauth_field1', 'field1_value');
authorizer.setField('oauth_field2', 'field2_value');

TwitterOAuth

var authorizer = new ApiClient.TwitterOAuth("<CONSUMER_KEY>", "<CONSUMER_SECRET>",
                                            "<TOKEN>", "<TOKEN_SECRET>");

Requests

GET

// ?TM=5979&MK=23979
client.get({
    params: {
        TM: '5979',
        MK: '23979'
    }
});

POST

client.post({
    content: {
        id: 5979,
        name: "Tanja"
    },
    
    type: ApiClient.HttpRequestType.JSON
});

PUT

client.put({
    content: '<user><id>23979</id><name>Marcel</name></user>',
    
    type: ApiClient.HttpRequestType.XML
});

PATCH

client.patch({
    content: '<user id="241279"><name>Julia</name></user>',
    
    type: ApiClient.HttpRequestType.XML
});

DELETE

client.delete({
    content: {
        id: 221286
    },
    
    type: ApiClient.HttpRequestType.JSON
});

Custom

client.request("FOO", {
    content: {
        TM: 5979,
        MK: 23979
    },
    
    type: ApiClient.HttpRequestType.JSON
});

Logging

If you want to log inside your result / error callbacks, you must define one or more logger actions in a client:

var client = ApiClient.newClient({
    baseUrl: "https://example.com/users",
    route: "{id}",  
});

client.addLogger(function(msg : ApiClient.ILogMessage) {
    console.log("[" + ApiClient.LogSource[msg.source] + "]: " + msg.message);
});

Each action receives an object of the following type:

interface ILogMessage {
    /**
     * Gets the category.
     */
    category: LogCategory;
    
    /**
     * Gets the message value.
     */
    message: any;
    
    /**
     * Gets the priority.
     */
    priority: LogPriority;
    
    /**
     * Gets the source.
     */
    source: LogSource;
    
    /**
     * Gets the tag.
     */
    tag: string;
    
    /**
     * Gets the timestamp.
     */
    time: Date;
}

Now you can starts logging in your callbacks:

client.clientError(function(result : ApiClient.IApiClientResult) {
                       result.warn("Client error: " + result.code);
                   })
      .serverError(function(result : ApiClient.IApiClientResult) {
                       result.err("Server error: " + result.code);
                   })
      .success(function(result : ApiClient.IApiClientResult) {
                    result.info("Success: " + result.code);
               })
      .error(function(err : ApiClient.IApiClientError) {
                 result.crit("API CLIENT ERROR!: " + err.error);
             })
      .completed(function(ctx : ApiClient.IApiClientCompleteContext) {
                     result.dbg("Completed action invoked.");
                 });

The IApiClientResult, IApiClientError and IApiClientCompleteContext objects using the ILogger interface:

interface ILogger {
    /**
     * Logs an alert message.
     * 
     * @param any msg The message value.
     * @param {String} [tag] The optional tag value.
     * @param {LogPriority} [priority] The optional log priority.
     */
    alert(msg : any, tag?: string,
          priority?: LogPriority) : ILogger;
    
    /**
     * Logs a critical message.
     * 
     * @param any msg The message value.
     * @param {String} [tag] The optional tag value.
     * @param {LogPriority} [priority] The optional log priority.
     */
    crit(msg : any, tag?: string,
         priority?: LogPriority) : ILogger;
    
    /**
     * Logs a debug message.
     * 
     * @param any msg The message value.
     * @param {String} [tag] The optional tag value.
     * @param {LogPriority} [priority] The optional log priority.
     */
    dbg(msg : any, tag?: string,
        priority?: LogPriority) : ILogger;
    
    /**
     * Logs an emergency message.
     * 
     * @param any msg The message value.
     * @param {String} [tag] The optional tag value.
     * @param {LogPriority} [priority] The optional log priority.
     */
    emerg(msg : any, tag?: string,
          priority?: LogPriority) : ILogger;
    
    /**
     * Logs an error message.
     * 
     * @param any msg The message value.
     * @param {String} [tag] The optional tag value.
     * @param {LogPriority} [priority] The optional log priority.
     */
    err(msg : any, tag?: string,
        priority?: LogPriority) : ILogger;
    
    /**
     * Logs an info message.
     * 
     * @param any msg The message value.
     * @param {String} [tag] The optional tag value.
     * @param {LogPriority} [priority] The optional log priority.
     */
    info(msg : any, tag?: string,
         priority?: LogPriority) : ILogger;
    
    /**
     * Logs a message.
     * 
     * @param any msg The message value.
     * @param {String} [tag] The optional tag value.
     * @param {LogCategory} [category] The optional log category. Default: LogCategory.Debug
     * @param {LogPriority} [priority] The optional log priority.
     */
    log(msg : any, tag?: string,
        category?: LogCategory, priority?: LogPriority) : ILogger;
    
    /**
     * Logs a notice message.
     * 
     * @param any msg The message value.
     * @param {String} [tag] The optional tag value.
     * @param {LogPriority} [priority] The optional log priority.
     */
    note(msg : any, tag?: string,
         priority?: LogPriority) : ILogger;
     
    /**
     * Logs a trace message.
     * 
     * @param any msg The message value.
     * @param {String} [tag] The optional tag value.
     * @param {LogPriority} [priority] The optional log priority.
     */
    trace(msg : any, tag?: string,
          priority?: LogPriority) : ILogger;
        
    /**
     * Logs a warning message.
     * 
     * @param any msg The message value.
     * @param {String} [tag] The optional tag value.
     * @param {LogPriority} [priority] The optional log priority.
     */
    warn(msg : any, tag?: string,
         priority?: LogPriority) : ILogger;
}

URL parameters

You can befine additional parameters for the URL.

If you create a client like this

var client = ApiClient.newClient({
    baseUrl: "https://api.example.com/users"
});

and start a request like this

client.get({
    params: {
        id: '23979',
        resource: "profile"
    }
});

The client will call the URL

[GET]  https://api.example.com/users?id=23979&resource=profile

Like route parameters you can also use functions for defining URL parameters:

var getUserId = function() : string {
    // load the user ID from somewhere
};

client.get({
    params: {
        id: getUserId,  // {id}
        resource: "profile"  // {resource}
    }
});

A function must have the following structure:

function (paramName: string, index: number, funcDepth: string) : any {
    return <THE-VALUE-TO-USE>;
}

IMPORTANT: It is also recommended to use / return strings a parameter values to prevent problems when converting the values to an URL string.

Responses

Callbacks

Simple

client.success(function(result : ApiClient.IApiClientResult) {
                    // handle any response
               });

The result object has the following structure:

interface IApiClientResult extends ILogger {
    /**
     * Gets the underlying API client.
     */
    client: IApiClient;

    /**
     * Gets the HTTP response code.
     */
    code: number;
    
    /**
     * Gets the raw content.
     */
    content: any;
    
    /**
     * Gets the underlying (execution) context.
     */
    context: ApiClientResultContext;
    
    /**
     * Gets the response headers.
     */
    headers: HTTP.Headers;
    
    /**
     * Returns the content as wrapped AJAX result object.
     * 
     * @return {IAjaxResult<TData>} The ajax result object.
     */
    getAjaxResult<TData>() : IAjaxResult<TData>;
    
    /**
     * Returns the content as file.
     * 
     * @param {String} [destFile] The custom path of the destination file.
     * 
     * @return {FileSystem.File} The file.
     */
    getFile(destFile?: string) : FileSystem.File;
    
    /**
     * Tries result the content as image source.
     */
    getImage(): Promise<Image.ImageSource>;
    
    /**
     * Returns the content as JSON object.
     */
    getJSON<T>() : T;
    
    /**
     * Returns the content as string.
     */
    getString() : string;
    
    /**
     * Gets the information about the request.
     */
    request: IHttpRequest;
    
    /**
     * Gets the raw response.
     */
    response: HTTP.HttpResponse;
}

Errors

client.error(function(err : ApiClient.IApiClientError) {
                 // handle an HTTP client error here
             });

The err object has the following structure:

interface IApiClientError extends ILogger {
    /**
     * Gets the underlying client.
     */
    client: IApiClient;
    
    /**
     * Gets the context.
     */
    context: ApiClientErrorContext;
    
    /**
     * Gets the error data.
     */
    error: any;
    
    /**
     * Gets or sets if error has been handled or not.
     */
    handled: boolean;
    
    /**
     * Gets the information about the request.
     */
    request: IHttpRequest;
}

Conditional callbacks

You can define callbacks for any kind of conditions.

A generic way to do this is to use the if() method:

client.if(function(result : IApiClientResult) : boolean {
              // invoke if 'X-My-Custom-Header' is defined
              return undefined !== result.headers["X-My-Custom-Header"];
          },
          function(result : IApiClientResult) {
              // handle the response
          });

If no condition matches, the callback defined by success() method is used.

For specific status codes you can use the ifStatus() method:

client.ifStatus((statusCode) => statusCode === 500,
                function(result : IApiClientResult) {
                    // handle the internal server error
                });

Or shorter:

client.status(500,
              function(result : IApiClientResult) {
                  // handle the internal server error
              });

Short hand callbacks

client.clientError(function(result : ApiClient.IApiClientResult) {
                       // handle status codes between 400 and 499
                   });
                   
client.ok(function(result : ApiClient.IApiClientResult) {
                       // handle status codes with 200, 204 or 205
                   });
                   
client.serverError(function(result : ApiClient.IApiClientResult) {
                       // handle status codes between 500 and 599
                   });

The following methods are also supported: