zoukankan      html  css  js  c++  java
  • Creating an API-Centric Web Application[转]

    Creating an API-Centric Web Application

    转自 http://hub.tutsplus.com/tutorials/creating-an-api-centric-web-application--net-23417

    by NIKKO BAUTISTA on DEC 30, 2011
    Difficulty: INTERMEDIATETime: LONGType: TUTORIAL

    Planning to start working on a new web application? In this tutorial, we'll discuss how to create an API-centric web application, and explain why this is essential in today's multi-platform world.

    Introduction

    API?

    For those who are unfamiliar with the term, API is short for Application Programming Interface. According to Wikipedia:

    An application programming interface (API) is a source code based specification intended to be used as an interface by software components to communicate with each other. An API may include specifications for routines, data structures, object classes, and variables.

     

    In simpler terms, an API refers to a set of functions built into an application, which can be used by other applications (or by itself, as we'll see later), to interact with the application. An API is a great way to expose an application's functionality to external applications safely and securely, since all functionality that these external applications can do is limited with what functionality is exposed in the API.

    What's an “API-Centric” Web Application?

    An API-Centric Web Application is a web application that basically executes most, if not, all its functionality through API calls.

     

    An API-Centric Web Application is a web application that basically executes most, if not, all its functionality through API calls. For example, if you were to log in a user, you would send his credentials to the API, and the API would return to you a result saying if the user provided the correct user-password combination.

    Another characteristic of an API-Centric Web Application is that the API will always be stateless, meaning it can't recognize API calls by session. Since API calls will be made by usually via the backend code, it will be hard to implement session handling, since there are usually no cookies involved in that. This limitation is actually good — this “forces” a developer to build an API that works not based on the state of the current user, but rather on functionality, which in turn, makes it easier to test, since the current state of a user doesn't need to be recreated.

    Why go through all this trouble?

    As web developers, we've seen technology evolve first hand. It's common knowledge that people today don't just use applications via a browser, but through other gadgets, like mobile phones and tablets. For example, this article on Mashable, entitled “Consumers Now Spending More Time on Mobile Apps Than the Web”, states:

    Consumers are spending more time on mobile apps than on the web for the first time, a new report claims.

     

    Flurry compared its mobile data to stats from comScore and Alexa, and found that in June, consumers spent 81 minutes per day using mobile apps, compared to 74 minutes of web surfing.

     

    Here's a more recent article from ReadWriteWeb, entitled “More People Browse On Mobile Than Use IE6 & IE7 Combined:

    The latest data on browser trends from Sitepoint show that more people browse the Web on smartphones than use Internet Explorer 6 and 7 combined. Those two old clunkers have been the bugbears of Web developers for years, requiring sites to degrade as nicely as possible to that least common denominator of browsers. But it's a new world now; 6.95% of Web activity in November 2011 was on mobile browsers, and only 6.49% was on IE 6 or 7.

     

    As we can clearly see, more and more people get their news from alternative venues, specifically mobile devices.

    What does this have to do with me creating an API-Centric Web Application?

    This would inevitably lead to more usage of our application, since it can be used anywhere a person wants.

     

    One of the main advantages of creating an API-centric application is that it helps you build functionality that can be used by ANY device, be it a browser, a mobile phone, a tablet, or even a desktop app. All you need to do is to create the API in such a way that all these devices can communicate with it, and voila! You'll have built a centralized application that can take input and execute functionality from any device that a person has!

    API-Centric Application Diagram

    API-Centric Application Diagram

    By creating an application in this manner, we're able to easily take advantage of the different mediums used by different people. This would inevitably lead to more usage of an application, since it can be used anywhere a person wants.

    To drive the point home, here's an article about Twitter's new redesigned website, which tells us about how they now use their API to power Twitter.com, essentially making it API-centric:

    One of the most important architectural changes is that Twitter.com is now a client of our own API. It fetches data from the same endpoints that the mobile site, our apps for iPhone, iPad, Android, and every third-party application use. This shift allowed us to allocate more resources to the API team, generating over 40 patches. In the initial page load and every call from the client, all data is now fetched from a highly optimized JSON fragment cache. 

    In this tutorial, we'll be creating a simple TODO list application that is API-Centric and create one front-end client on the browser that interacts with our TODO list application. By the end, you'll know the integral parts of an API-Centric application, and at the same time, how to facilitate secure communication between the two. With that in mind, let's begin!

    Step 1: Plan the Application's Functions

    The TODO application we'll be building in this tutorial will have the basic CRUD functions:

    • Create TODO Items
    • Read TODO Items
    • Update TODO Items (rename, mark as done, mark as undone)
    • Delete TODO Items

    Each TODO item will have:

      • Title
      • Date Due
      • Description
      • a flag to tell if the TODO Item Is Done

    Let's mockup the application as well so we have a guide on how it should look like afterwards:

    SimpleTODO Mockup

    SimpleTODO Mockup

    Step 2: Create the API Server

    Since we're developing an API-Centric application, we'll be creating two “projects”: the API Server, and the Front-end Client. Let's begin by creating the API server first.

    On your web server's folder, create a folder named simpletodo_api, and create an index.php file. This index.php file will act as a front controllerfor the API, so all requests to the API server will be made through this file. Open it up and put the following code inside:

    01
    02
    03
    04
    05
    06
    07
    08
    09
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    <?php
    // Define path to data folder
    define('DATA_PATH', realpath(dirname(__FILE__).'/data'));
     
    //include our models
    include_once 'models/TodoItem.php';
     
    //wrap the whole thing in a try-catch block to catch any wayward exceptions!
    try {
        //get all of the parameters in the POST/GET request
        $params = $_REQUEST;
         
        //get the controller and format it correctly so the first
        //letter is always capitalized
        $controller = ucfirst(strtolower($params['controller']));
         
        //get the action and format it correctly so all the
        //letters are not capitalized, and append 'Action'
        $action = strtolower($params['action']).'Action';
     
        //check if the controller exists. if not, throw an exception
        if( file_exists("controllers/{$controller}.php") ) {
            include_once "controllers/{$controller}.php";
        } else {
            throw new Exception('Controller is invalid.');
        }
         
        //create a new instance of the controller, and pass
        //it the parameters from the request
        $controller = new $controller($params);
         
        //check if the action exists in the controller. if not, throw an exception.
        if( method_exists($controller, $action) === false ) {
            throw new Exception('Action is invalid.');
        }
         
        //execute the action
        $result['data'] = $controller->$action();
        $result['success'] = true;
         
    } catch( Exception $e ) {
        //catch any exceptions and report the problem
        $result = array();
        $result['success'] = false;
        $result['errormsg'] = $e->getMessage();
    }
     
    //echo the result of the API call
    echo json_encode($result);
    exit();

    What we've essentially built here is a simple front controller that does the following:

        • Accept an API call with any number of parameters
        • Extract the Controller and Action for the API call
        • Make the necessary checks to ensure that the Controller and Actionexist
        • Execute the API call
        • Catch errors, if any
        • Send back a result to the caller

    Besides the index.php file, create three folders: a controllersmodels anddata folder.

    API server folders
        • The controllers folder will contain all the controllers we'll be using for the API server. We'll be building it using the MVC architecture to make the structure of the API server cleaner and more organized.
        • The models folder will contain all the data models for the API server.
        • The data folder will be where the API server saves any data

    Go into the controllers folder and create a file called Todo.php. This will be our controller for any TODO list related tasks. With the functions we'll be needing for our TODO application in mind, create the necessary methods for the Todo controller:

    01
    02
    03
    04
    05
    06
    07
    08
    09
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    <?php
    class Todo
    {
        private $_params;
         
        public function __construct($params)
        {
            $this->_params = $params;
        }
         
        public function createAction()
        {
            //create a new todo item
        }
         
        public function readAction()
        {
            //read all the todo items
        }
         
        public function updateAction()
        {
            //update a todo item
        }
         
        public function deleteAction()
        {
            //delete a todo item
        }
    }

    Now, add the necessary functionality to each action. I'll provide the code for the createAction method and I'll leave it up to you to create the code for the other methods. If you're not in the mood though, you can just download the source code for the demo and copy it from there.

    01
    02
    03
    04
    05
    06
    07
    08
    09
    10
    11
    12
    13
    14
    15
    public function createAction()
    {
        //create a new todo item
        $todo = new TodoItem();
        $todo->title = $this->_params['title'];
        $todo->description = $this->_params['description'];
        $todo->due_date = $this->_params['due_date'];
        $todo->is_done = 'false';
         
        //pass the user's username and password to authenticate the user
        $todo->save($this->_params['username'], $this->_params['userpass']);
         
        //return the todo item in array format
        return $todo->toArray();
    }

    Create TodoItem.php inside the models folder so we can create the “item creation” code. Take note that I won't be connecting to a database, rather, I'll be saving the information into files. It should be relatively easy though to make this work with any database.

    01
    02
    03
    04
    05
    06
    07
    08
    09
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    <?php
    class TodoItem
    {
        public $todo_id;
        public $title;
        public $description;
        public $due_date;
        public $is_done;
         
        public function save($username, $userpass)
        {
            //get the username/password hash
            $userhash = sha1("{$username}_{$userpass}");
            if( is_dir(DATA_PATH."/{$userhash}") === false ) {
                mkdir(DATA_PATH."/{$userhash}");
            }
             
            //if the $todo_id isn't set yet, it means we need to create a new todo item
            if( is_null($this->todo_id) || !is_numeric($this->todo_id) ) {
                //the todo id is the current time
                $this->todo_id = time();
            }
             
            //get the array version of this todo item
            $todo_item_array = $this->toArray();
             
            //save the serialized array version into a file
            $success = file_put_contents(DATA_PATH."/{$userhash}/{$this->todo_id}.txt", serialize($todo_item_array));
             
            //if saving was not successful, throw an exception
            if( $success === false ) {
                throw new Exception('Failed to save todo item');
            }
             
            //return the array version
            return $todo_item_array;
        }
         
        public function toArray()
        {
            //return an array version of the todo item
            return array(
                'todo_id' => $this->todo_id,
                'title' => $this->title,
                'description' => $this->description,
                'due_date' => $this->due_date,
                'is_done' => $this->is_done
            );
        }
    }

    The createAction method calls two functions on the TodoItem model:

        • save() - this saves the TodoItem into a file, as well as set the todo_id for the TodoItem if necessary
        • toArray() - this returns an array version of the TodoItem, where the variables are the array's indexes

    Since the API is called via HTTP requests, let's test that API call by calling it through the browser:

    http://localhost/simpletodo_api/?controller=todo&action=create&title=test%20title&description=test%20description&due_date=12/08/2011&username=nikko&userpass=test1234

    If everything worked, you should see a new folder inside the data folder, and inside that folder, you should see a file with the following content:

    createAction() result

    createAction() result

    Congratulations! You've successfully created an API server and made an API call!

    Step 3: Secure the API Server with an APP ID and APP SECRET

    Currently, the API server is set to accept ALL API requests. We'll need to limit it to our own applications only, to ensure that only our own front-end clients are able to make API requests. Alternatively, you can actually create a system wherein users can create their own applications that have access to your API server, similar to how Facebook and Twitter applications work.

    Begin by creating a set of id-key pairs for the clients that will be using the API server. Since this is just a demo, we can use any random, 32 character string. For the APP ID, let's say it's application APP001.

    Open the index.php file again, and then update it with the following code:

    01
    02
    03
    04
    05
    06
    07
    08
    09
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    <?php
    // Define path to data folder
    define('DATA_PATH', realpath(dirname(__FILE__).'/data'));
     
    //Define our id-key pairs
    $applications = array(
        'APP001' => '28e336ac6c9423d946ba02d19c6a2632', //randomly generated app key
    );
    //include our models
    include_once 'models/TodoItem.php';
     
    //wrap the whole thing in a try-catch block to catch any wayward exceptions!
    try {
        //*UPDATED*
        //get the encrypted request
        $enc_request = $_REQUEST['enc_request'];
         
        //get the provided app id
        $app_id = $_REQUEST['app_id'];
         
        //check first if the app id exists in the list of applications
        if( !isset($applications[$app_id]) ) {
            throw new Exception('Application does not exist!');
        }
         
        //decrypt the request
        $params = json_decode(trim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $applications[$app_id], base64_decode($enc_request), MCRYPT_MODE_ECB)));
         
        //check if the request is valid by checking if it's an array and looking for the controller and action
        if( $params == false || isset($params->controller) == false || isset($params->action) == false ) {
            throw new Exception('Request is not valid');
        }
         
        //cast it into an array
        $params = (array) $params;
        ...
        ...
        ...

    What we've done here is actually implement a very simple way of authenticating our front-end clients using a system similar to public-private key authentication. Basically, here is the step-by-step breakdown of how the authentication happens:

    Public-key encryption

    Public-key encryption
        • an API call is made, in it an $app_id and $enc_request is provided.
        • the $enc_request value is the API call parameters, encrypted using APP KEY. The APP KEY is NEVER sent to the server, it's only used to hash the request. Additionally, the request can only be decrypted using the APP KEY.
        • once the API call arrives to the API server, it will check its own list of applications for the APP ID provided
        • when found, the API server attempt to decrypt the request using the key that matches the APP ID sent
        • if it was successful in decrypting it, then continue on with the program

    Now that the API server is secured with an APP ID and APP SECRET, we can begin programming a front-end client to use the API server.

    Step 4: Create the Browser Front-end Client

    We'll begin by setting up a new folder for the front-end client. Create a folder called simpletodo_client_browser on your web server's folder. When that's done, create an index.php file and put this code inside:

    01
    02
    03
    04
    05
    06
    07
    08
    09
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    <!DOCTYPE html>
    <html>
    <head>
        <title>SimpleTODO</title>
         
        <link rel="stylesheet" href="css/reset.css" type="text/css" />
        <link rel="stylesheet" href="css/bootstrap.min.css" type="text/css" />
         
        <script src="js/jquery.min.js"></script>
        <script src="js/jquery-ui-1.8.16.custom.min.js"></script>
         
        <style>
        body {
            padding-top: 40px;
        }
        #main {
            margin-top: 80px;
            text-align: center;
        }
        </style>
    </head>
    <body>
        <div class="topbar">
            <div class="fill">
                <div class="container">
                    <a class="brand" href="index.php">SimpleTODO</a>
                </div>
            </div>
        </div>
        <div id="main" class="container">
            <form class="form-stacked" method="POST" action="login.php">
                <div class="row">
                    <div class="span5 offset5">
                        <label for="login_username">Username:</label>
                        <input type="text" id="login_username" name="login_username" placeholder="username" />
                     
                        <label for="login_password">Password:</label>
                        <input type="password" id="login_password" name="login_password" placeholder="password" />
                         
                    </div>
                </div>
                <div class="actions">
                    <button type="submit" name="login_submit" class="btn primary large">Login or Register</button>
                </div>
            </form>
        </div>
    </body>
    </html>

    That should look something like this:

    SimpleTODO Login Page

    SimpleTODO Login Page

    Take note that I've included 2 JavaScript files and 2 CSS files here:

    Next, let's create the login.php file so we store the username and password inside a session on the client.

    01
    02
    03
    04
    05
    06
    07
    08
    09
    10
    11
    <?php
    //get the form values
    $username = $_POST['login_username'];
    $userpass = $_POST['login_password'];
     
     
    session_start();
    $_SESSION['username'] = $username;
    $_SESSION['userpass'] = $userpass;
    header('Location: todo.php');
    exit();

    Here, we simply start a session for the user, based on the username and password combination the user will provide. This acts as a simple combination key, which will allow a user to access stored TODO items for a specific combination of both the username and password. We then redirect to todo.php, where we start interacting with the API server. Before we start coding the todo.php file though, let's first create an ApiCaller class, which will encapsulate all the API calling methods we'll need, including encrypting the requests.

    Create apicaller.php and put the following inside:

    01
    02
    03
    04
    05
    06
    07
    08
    09
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    52
    53
    54
    55
    56
    57
    58
    <?php
    class ApiCaller
    {
        //some variables for the object
        private $_app_id;
        private $_app_key;
        private $_api_url;
         
        //construct an ApiCaller object, taking an
        //APP ID, APP KEY and API URL parameter
        public function __construct($app_id, $app_key, $api_url)
        {
            $this->_app_id = $app_id;
            $this->_app_key = $app_key;
            $this->_api_url = $api_url;
        }
         
        //send the request to the API server
        //also encrypts the request, then checks
        //if the results are valid
        public function sendRequest($request_params)
        {
            //encrypt the request parameters
            $enc_request = base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $this->_app_key, json_encode($request_params), MCRYPT_MODE_ECB));
             
            //create the params array, which will
            //be the POST parameters
            $params = array();
            $params['enc_request'] = $enc_request;
            $params['app_id'] = $this->_app_id;
             
            //initialize and setup the curl handler
            $ch = curl_init();
            curl_setopt($ch, CURLOPT_URL, $this->_api_url);
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
            curl_setopt($ch, CURLOPT_POST, count($params));
            curl_setopt($ch, CURLOPT_POSTFIELDS, $params);
     
            //execute the request
            $result = curl_exec($ch);
             
            //json_decode the result
            $result = @json_decode($result);
             
            //check if we're able to json_decode the result correctly
            if( $result == false || isset($result['success']) == false ) {
                throw new Exception('Request was not correct');
            }
             
            //if there was an error in the request, throw an exception
            if( $result['success'] == false ) {
                throw new Exception($result['errormsg']);
            }
             
            //if everything went great, return the data
            return $result['data'];
        }
    }

    We'll be using the ApiCaller class to send requests to our API server. This way, all the necessary encryption and cURL initialization code will be in one place, and we won't have to repeat our code.

        • the __construct function takes in three parameters:
          1. $app_id - the APP ID for the client (which is APP001 for the browser client)
          2. $app_key - the APP KEY for the client (which is28e336ac6c9423d946ba02d19c6a2632 for the browser client)
          3. $api_url - the URL of the API server, which ishttp://localhost/simpletodo_api/
        • the sendRequest() function:
          1. encrypts the request parameters using the mcrypt library in the same manner that the API server decrypts it
          2. generates the $_POST parameters to be sent to the API server
          3. executes the API call via cURL
          4. checks the result of the API call was successful or not
          5. returns the data when everything went according to plan

    Now, let's begin with the todo.php page. First off, let's create some code to retrieve the current list of todo items for the user nikko with the passwordtest1234 (this is the user/password combination we used earlier to test the API server).

    01
    02
    03
    04
    05
    06
    07
    08
    09
    10
    11
    12
    13
    14
    15
    <?php
    session_start();
    include_once 'apicaller.php';
     
    $apicaller = new ApiCaller('APP001', '28e336ac6c9423d946ba02d19c6a2632', 'http://localhost/simpletodo_api/');
     
    $todo_items = $apicaller->sendRequest(array(
        'controller' => 'todo',
        'action' => 'read',
        'username' => $_SESSION['username'],
        'userpass' => $_SESSION['userpass']
    ));
     
    echo '';
    var_dump($todo_items);

    Go to the index.php page, login as nikko/test1234, and you should see avar_dump() of the TODO item we created earlier.

    TODO item var_dump()

    Congratulations, you've successfully made an API call to the API server! In this code, we've:

        • started the session so we have access to the username and userpass in the $_SESSION
        • instantiated a new ApiCaller class, giving it the APP IDAPP KEY and the URL of the API server
        • send a request via the sendRequest() method

    Now, let's reformat the data so it looks better. Add the following HTML to the todo.php code. Don't forget to remove the var_dump()!

    001
    002
    003
    004
    005
    006
    007
    008
    009
    010
    011
    012
    013
    014
    015
    016
    017
    018
    019
    020
    021
    022
    023
    024
    025
    026
    027
    028
    029
    030
    031
    032
    033
    034
    035
    036
    037
    038
    039
    040
    041
    042
    043
    044
    045
    046
    047
    048
    049
    050
    051
    052
    053
    054
    055
    056
    057
    058
    059
    060
    061
    062
    063
    064
    065
    066
    067
    068
    069
    070
    071
    072
    073
    074
    075
    076
    077
    078
    079
    080
    081
    082
    083
    084
    085
    086
    087
    088
    089
    090
    091
    092
    093
    094
    095
    096
    097
    098
    099
    100
    101
    102
    103
    104
    <!DOCTYPE html>
    <html>
    <head>
        <title>SimpleTODO</title>
         
        <link rel="stylesheet" href="css/reset.css" type="text/css" />
        <link rel="stylesheet" href="css/bootstrap.min.css" type="text/css" />
        <link rel="stylesheet" href="css/flick/jquery-ui-1.8.16.custom.css" type="text/css" />
         
        <script src="js/jquery.min.js"></script>
        <script src="js/jquery-ui-1.8.16.custom.min.js"></script>
         
        <style>
        body {
            padding-top: 40px;
        }
        #main {
            margin-top: 80px;
        }
         
        .textalignright {
            text-align: right;
        }
         
        .marginbottom10 {
            margin-bottom: 10px;
        }
        #newtodo_window {
            text-align: left;
            display: none;
        }
        </style>
         
        <script>
        $(document).ready(function() {
            $("#todolist").accordion({
                collapsible: true
            });
            $(".datepicker").datepicker();
            $('#newtodo_window').dialog({
                autoOpen: false,
                height: 'auto',
                 'auto',
                modal: true
            });
            $('#newtodo').click(function() {
                $('#newtodo_window').dialog('open');
            });
        });
        </script>
    </head>
    <body>
        <div class="topbar">
            <div class="fill">
                <div class="container">
                    <a class="brand" href="index.php">SimpleTODO</a>
                </div>
            </div>
        </div>
        <div id="main" class="container">
            <div class="textalignright marginbottom10">
                <span id="newtodo" class="btn info">Create a new TODO item</span>
                <div id="newtodo_window" title="Create a new TODO item">
                    <form method="POST" action="new_todo.php">
                        <p>Title:<br /><input type="text" class="title" name="title" placeholder="TODO title" /></p>
                        <p>Date Due:<br /><input type="text" class="datepicker" name="due_date" placeholder="MM/DD/YYYY" /></p>
                        <p>Description:<br /><textarea class="description" name="description"></textarea></p>
                        <div class="actions">
                            <input type="submit" value="Create" name="new_submit" class="btn primary" />
                        </div>
                    </form>
                </div>
            </div>
            <div id="todolist">
                <?php foreach($todo_items as $todo): ?>
                <h3><a href="#"><?php echo $todo->title; ?></a></h3>
                <div>
                    <form method="POST" action="update_todo.php">
                    <div class="textalignright">
                        <a href="delete_todo.php?todo_id=<?php echo $todo->todo_id; ?>">Delete</a>
                    </div>
                    <div>
                        <p>Date Due:<br /><input type="text" id="datepicker_<?php echo $todo->todo_id; ?>" class="datepicker" name="due_date" value="12/09/2011" /></p>
                        <p>Description:<br /><textarea class="span8" id="description_<?php echo $todo->todo_id; ?>" class="description" name="description"><?php echo $todo->description; ?></textarea></p>
                    </div>
                    <div class="textalignright">
                        <?php if( $todo->is_done == 'false' ): ?>
                        <input type="hidden" value="false" name="is_done" />
                        <input type="submit" class="btn" value="Mark as Done?" name="markasdone_button" />
                        <?php else: ?>
                        <input type="hidden" value="true" name="is_done" />
                        <input type="button" class="btn success" value="Done!" name="done_button" />
                        <?php endif; ?>
                        <input type="hidden" value="<?php echo $todo->todo_id; ?>" name="todo_id" />
                        <input type="hidden" value="<?php echo $todo->title; ?>" name="title" />
                        <input type="submit" class="btn primary" value="Save Changes" name="update_button" />
                    </div>
                    </form>
                </div>
                <?php endforeach; ?>
            </div>
        </div>
    </body>
    </html>

    It should now look something like this:

    TODO Home

    Pretty cool huh? But this currently does nothing, so let's begin adding some functionality. I'll provide the code for new_todo.php, which will call thetodo/create API call to create a new TODO item. Creating the other pages (update_todo.php and delete_todo.php) should be very similar to this one, so I'll leave it up to you to create those. Open up new_todo.php and add the following code:

    01
    02
    03
    04
    05
    06
    07
    08
    09
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    <?php
    session_start();
    include_once 'apicaller.php';
     
    $apicaller = new ApiCaller('APP001', '28e336ac6c9423d946ba02d19c6a2632', 'http://localhost/simpletodo_api/');
     
    $new_item = $apicaller->sendRequest(array(
        'controller' => 'todo',
        'action' => 'create',
        'title' => $_POST['title'],
        'due_date' => $_POST['due_date'],
        'description' => $_POST['description'],
        'username' => $_SESSION['username'],
        'userpass' => $_SESSION['userpass']
    ));
     
    header('Location: todo.php');
    exit();
    ?>

    As you can see, the new_todo.php page uses the ApiCaller again to facilitate the sending the todo/create request to the API server. This basically does the same thing as before:

        • start a session so it has access to the $username and $userpass saved in the $_SESSION
        • instantiate a new ApiCaller class, giving it the APP IDAPP KEY and the URL of the API server
        • send the request via the sendRequest() method
        • redirect back to todo.php
    New TODO!

    Congratulations, it works! You've successfully created an API-centric application!

    Conclusion

    There are so many advantages to developing an application that's built around an API. Want to create an Android application version of SimpleTODO? All the functionality you would need is already in the API server, so all you need to do is just create the client! Want to refactor or optimize some of the classes? No problem — just make sure the output is the same. Need to add more functionality? You can do it wihtout affecting any of the client's code!

    Though there are some disadvantages like longer development times or more complexity, the advantages of developing a web application in this manner greatly outweight the disadvantages. It's up to us to leverage on this kind of development today so we can reap the benefits later on.

    Are you planning to use an API server for your next web application, or have you already used the same technique for a project in the past? Let me know in the comments!

  • 相关阅读:
    【解决】Linux Tomcat启动慢Creation of SecureRandom instance for session ID generation using [SHA1PRNG] took [236,325] milliseconds
    初学java总结
    第8周课程总结&实验报告6
    第9周总结&实验报告7
    实验报告5&第七周课程总结
    第五周课程总结、实验报告三
    第六周总结&实验报告四
    使用REST接口获取GeoServer中的图层列表
    网上最流行的FLASH焦点图文幻灯片(focus.swf改进版),可支持jpg/gif/png/swf文件(转载)
    使用PostgreSQL的bytea字段存读取文件及读取出错问题处理
  • 原文地址:https://www.cnblogs.com/nobcool/p/3340297.html
Copyright © 2011-2022 走看看