Steps to obtain user avatar when accessing WeChat

I wrote about WeChat payment access some time ago, and by the way to obtain user nicknames and avatars, this is actually quite simple, just read the official document for the specific method. Here are only a few key points.

scope parameter

If you have read the WeChat document, WeChat stipulates that for scope parameters, if you need to obtain user information, the scope parameter is snsapi_userinfo. But next, I used userinfo once, and in fact, I can also get user information with snsapi_base, with the same return value, and there is no problem with getting the avatar and nickname.

Get avatar

The one thing that is actually a bit troublesome about getting avatar is the cross-domain problem. To solve this cross-domain problem, you can set up a proxy server, or configure the relevant server (ngix, apache). There are many methods online, and what I am talking about here is a method that does not pass the configuration of the server.

In our project, I do not want to configure a web server or proxy, because we are a game server, we implement it ourselves, and do not use any web server framework. In this case, our solution to the cross-domain problem is that our server backend directly initiates a request for cross-domain resources, and after obtaining the corresponding resources, we return to the frontend. OK, this is the specific method

When implementing it in detail, it is actually very simple. After obtaining the url of the avatar, directly initiate an http request and get the return.

Note: http request method is "GET"

Another point that needs to be mentioned is that the return of the response should be used directly. If you use the streamReader, the data read from the byte stream cannot be converted into a picture in text. (I have consulted MSDN's instructions on these two interfaces, but when reading one is in text form and the other is in byte stream form. There is no too much difference.)

Then remember to convert the byte stream in Base64 and hand it over to our front-end to process

request = (url);
 = "GET";
response = ();
stream = ();
var buffer = new byte[4096];
var num = (buffer, 0, 4096);
var head = Convert.ToBase64String(buffer, 0, num);

();
();

There is a problem with the above code. I later noticed that when the image is relatively large, for example, the last parameter of the avatar address is above 64, or /0 (the image of size 640*640 is returned at this time), the stream may not be able to read all the data at once, so the code is modified to

var request = (url);
 = "GET";
var response = ();
var stream = ();
var buffer = new byte[];
var num = (buffer, 0, (int));
var total = num;
while(num > 0)
{
  num = (buffer, total, (int)( - total));
  total += num;
}
head = Convert.ToBase64String(buffer, 0, total);

The above is all the content of this article. I hope it will be helpful to everyone's study and I hope everyone will support me more.