How to solve the problem that uniapp package cannot request data?

With the popularity of mobile applications, there is an increasing need to develop mobile applications. What follows is an increasing demand for cross-platform development. Uniapp is a cross-platform development framework that emerged to meet this development demand. Since cross-platform development needs to take into account some limitations and differences on different platforms, the development difficulty has also increased slightly. Among them, during the packaging process, you may encounter the problem of requesting data failure. Next, let's discuss the problem of uniapp packaging request failure. Data causes and solutions.

First of all, it needs to be clear that uniapp is a cross-platform development framework based on Vue.js, so it needs to follow the development specifications of Vue.js during the development process. In the Vue.js framework, requesting data is usually completed through a unified entrance—the created hook function of the Vue instance. In uniapp, we usually use the onLoad component life cycle function to complete data requests.

So, why can’t I request data after uniapp is packaged? First of all, we need to know that during the development stage, we may have cross-domain problems. Because during the development phase we usually develop by directly accessing the local API of the server, and after uniapp is packaged, our applications will be deployed to different platforms or servers, which introduces cross-domain issues and results in requesting data. fail.

Secondly, in uniapp, we usually use the uni.request() method to request data, and this method does not carry cookies by default. If our API needs to carry cookies for verification, we need to set withCredentials property is true, otherwise the request will fail.

In addition, in uniapp, we may use some third-party libraries to perform data requests, such as axios, etc. When using these libraries, you need to pay attention to the different usage methods on different platforms. For example, on the H5 platform, we can use the XMLHttpRequest object to make data requests, while on the mini program platform, we need to use wx.request().

So, how to solve the problem that uniapp package cannot request data? The solution is as follows:

1. During the development stage, pay attention to enabling the CORS permission of the server API to avoid cross-domain problems.
2. When requesting data, set the withCredentials attribute to true.
3. Use the correct API for data requests on different platforms.
4. For the uni.request() method, we can encapsulate it into the instance method of Vue to facilitate unified use and calling.
5. In uniapp, we can use the uni-app-plus plug-in, which provides underlying native API support for uniapp and can handle requests from various platforms more flexibly.

In short, to solve the problem that uniapp package cannot request data, you mainly need to pay attention to cross-domain issues and the use of different platform APIs, as well as details such as configuring request parameters. In the actual development process, we need to constantly try and debug to find the best solution.

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