Actual combat of flutter - Request encapsulation (I)

It took two years flutter, Have some experience , Some cases will be updated from today , Not empty head and brain , Only for practical use , For study or use flutter My little friend's reference , Learning is still shallow , If there is anything wrong, we hope all gods will correct it , So as not to mislead others , Thank you here. ~（ Originality is not easy. , Please indicate the source and author when forwarding ）

Be careful ： No special instructions ,flutter Version is 3.0+

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         Development of all programs , Including native development ,web front end , Small programs inevitably do one thing, that is, encapsulate the requests that interact with the background , Then it is convenient to receive data , So let's take it step by step today flutter The package of is written clearly .

One . Module partition

A good project structure should be clearly divided into modules , Include api request , for instance

such as base Based on api, Include login , register , Set interfaces .bi Interface for report statistics , And so on , goods , Orders and so on .

Two . Request to packaging

Let's first look at the packaging requirements
1. The request url Defined in the head , Easy to find and modify

2. Encapsulation request method HttpUtils（ We will talk about this in a new chapter ）

3. Define the entity classes requested and returned . There are several cases of general interface return

• Return information such as success , The result could be String,bool
• Return an entity class , For example, user information UserDo
• Return the list of entity classes ,List<Object>, Enter and return the permission list of the login user

Let's look at a simple example of three types ：

class UserApi {
/// Query login user
static const String _getUser = "/base/login/user";

/// Sign in
static const String _login ="/base/login";

// Query login permission

static const _selectPermission = "/base/selectPermission";

static Future<UserDo> getUser() async {
&nbsp;&nbsp;&nbsp;&nbsp;var res = await HttpUtils.get(_getUser, baseUrl: Config.BASE_API_URL);
&nbsp;&nbsp;&nbsp;&nbsp;return UserDo.fromJson(res);
}

static Future<String> login(dynamic param) async {
&nbsp;&nbsp;&nbsp;&nbsp;var res = await HttpUtils.post(_login, data: param, baseUrl: &nbsp;&nbsp;&nbsp;&nbsp;Config.BASE_API_URL, showLoading: showLoad);
&nbsp;&nbsp;&nbsp;&nbsp;return res;
}

static Future<List<Permission>> selectPermission(List<String> permissions) async {
var res = await HttpUtils.post(
&nbsp;&nbsp;&nbsp;&nbsp;_selectPermission,
&nbsp;&nbsp;&nbsp;&nbsp;data: permissions,
&nbsp;&nbsp;&nbsp;&nbsp;baseUrl: Config.BASE_API_URL,
);
returnres.map<Permission>((e) => Permission.fromJson(e)).toList();
}

3、 ... and .Json Handle ：FlutterJsonBeanFactory

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Dart Language in Json The aspect framework of transformation is not mature , There is no such thing Java And other language reflection mechanisms , If you manually process the conversion of the returned results , It will be a very troublesome thing , Fortunately, there are still many great gods , Here is a recommended conversion tool FlutterJsonBeanFactory, Can be generated quickly , And you can use the conversion method in the above example ：fromJson and toJson.

Installation method ：

Settings/Preferences > Plugins > Marketplace > Search for "FlutterJsonBeanFactory" > Install Plugin

The current use is 4.4.5 edition . Thank the author for upgrading all the way , Also witnessed the plug-in from if Judge , To Map The transformation of , More efficient search .

Use ：

take PostMan Return result of , Copy directly in the creation window of the tool , According to the type

Generating entities

Of course, entity type nesting is also supported .

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Conclusion ：

Interested readers can study the source code by themselves .

Add in address ：https://plugins.jetbrains.com/plugin/11415-flutterjsonbeanfactory-only-null-safety-