How to use PHP to implement the camera function in WeChat applet

With the vigorous promotion of WeChat mini programs, more and more developers want to add some interesting interactive methods to mini programs, among which the camera function is indispensable. In this article, we will introduce how to use PHP to implement the camera function in the WeChat applet.

Prerequisites for development

Before starting development, we need to have the following technologies and software:

• Basics of WeChat Mini Program Development
• PHP language Basic
• WeChat mini program official API (WxRequest) to obtain user authorization
• PHP image processing library GD expansion module
• The mini program background storage server, it is recommended to use cloud services, such as Alibaba Cloud, Tencent Cloud, etc.

Steps to implement the WeChat mini program’s camera function using PHP

1. The mini program obtains user authorization

The mini program needs to obtain user permission and authorization , to use the camera function. Use the wx.authorize method in the mini program to obtain user authorization.

2. The applet opens the camera and takes pictures

The applet uses the wx.chooseImage method to open the camera of the user device, and after the photo is taken, the photo is saved in a temporary folder.

3. Upload the photos in the temporary folder to the server

Use the wx.uploadFile method to upload the photos in the temporary folder to the server.

4. Use PHP language for image processing

After the server receives the uploaded photo, it uses PHP language to process the image and save the processed image on the server.

Below we will introduce the specific implementation method of each step in detail.

The mini program obtains user authorization

The mini program needs to obtain user authorization before it can use the camera function. Use the wx.authorize method in the mini program to obtain user authorization.

You can first define a function in the app.js file of the mini program:

//授权获取用户摄像头权限
function takePhoto() {
  wx.authorize({
    scope: 'scope.camera',
    success: function () {
      console.log("授权成功");
      //调用打开摄像头代码
      choosePhoto();
    },
    fail: function () {
      console.log("授权失败");
    }
  })
}

After the user confirms authorization, call the choosePhoto() function to turn on the camera function.

The applet opens the camera and takes pictures

After the user authorizes it, we need to use the wx.chooseImage method in the applet to open the camera of the user's device and perform the corresponding photo operation. What needs to be noted here is that we need to save the photos after taking them in a temporary folder.

Continue to define the choosePhoto() function in app.js of the mini program. This function will automatically open the camera and take pictures, and save the taken photos in a temporary folder:

// 打开照相并进行拍照
function choosePhoto() {
  wx.chooseImage({
    count: 1, // 可以选择的图片数量
    sizeType: ['original', 'compressed'], // 可以指定是原图还是压缩图
    sourceType: ['album', 'camera'], // 可以指定来源是相册还是相机
    success: function (res) {
      // 将拍照后的照片保存在本地文件夹中
      var tempFilePaths = res.tempFilePaths
      wx.uploadFile({
        url: '服务器地址',
        filePath: tempFilePaths,
        name: 'file',
        success: function (res) {
          var data = res.data;
          console.log(data);
        },
        fail: function (res) {
          console.log(res);
        }
      })
    }
  })
}

Here, the wx.chooseImage method is used to obtain the photos taken by the user, and the wx.uploadFile method is used to upload the photos to the server.

Upload the photos in the temporary folder to the server

After successfully obtaining the photos taken by the user, we need to upload them to the server for processing. The code to upload to the server using the wx.uploadFile method is as follows:

    wx.uploadFile({
        url: '服务器地址',
        filePath: tempFilePaths,
        name: 'file',
        success: function (res) {
          var data = res.data;
          console.log(data);
        },
        fail: function (res) {
          console.log(res);
        }
      })

The server address here needs to be specified as the path to the PHP file where the uploaded photos are located. For example: http://www.example.com/upload.php

Use PHP language for image processing

PHP is a very useful server-side scripting language. We can use PHP to The uploaded photos are processed to achieve the effect we want.

Libraries that use PHP language to process images are usually GD expansion modules and need to be installed on the server. Through PHP's GD expansion module, we can perform the following processing operations: image compression, image rotation, image scaling, etc.

For the photos that need to be processed, we can first download them from the server to the local area, and then perform corresponding operations on them. The approximate code is as follows:

//下载服务器照片
$img = 'http://www.example.com/image.jpg';
$localimage = './image.jpg';
$imgcontent = file_get_contents($img);
file_put_contents($localimage, $imgcontent);
//使用GD库进行图片的缩放处理
$image = imagecreatefromjpeg($localimage);
$x = imagesx($image);
$y = imagesy($image);
$xnew = 100 ;//新图片大小
$ynew = 100 ;//新图片大小
$image_p = imagecreatetruecolor($xnew, $ynew);
imagecopyresampled($image_p, $image, 0,0,0,0, $xnew,$ynew,$x,$y);
imagepng($image_p, $localimage);//将处理后的图片保存
imagedestroy($image_p);
imagedestroy($image);

Through the above operations, we can use PHP on the server to process the photos uploaded by the user, and save the processed photos on the server.

Conclusion

This article introduces how to use PHP to implement the photo taking function in the WeChat applet, including user authorization, opening the camera and taking photos, uploading the photos to the server, and the server processing the photos. Through the above technical means, we can easily realize the interesting photo taking function in the WeChat mini program, and add more fun and experience to the users of the mini program.

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