callback.adoc

Implement the Callback

Reference https://developer.github.com/v3/oauth/#2-github-redirects-back-to-your-site

Now we need to convert the code that we received into an access_token

1. Add a controller to response to the callback request

   RestTemplate restTemplate = new RestTemplate();
   
   @GetMapping("/callback")
   @ResponseBody
   Object callback(@RequestParam String code) {
   
     HashMap response = restTemplate.postForEntity("https://github.com/login/oauth/access_token?" +
         "client_id=13e67f9acf45a46a6567&" +
         "client_secret=dc51ddd68a03ff435a497b3023b44a37b55fbc1d&" +
         "code=" + code, null, HashMap.class).getBody();
   
     return response.toString();
   }

2. Go to http://localhost:8080/ and click Login with Github button again

   

3. Extract access_token in a type safe manner, add a token class

   class GithubTokenResponse {
   
     private final String accessToken;
   
     @JsonCreator
     public GithubTokenResponse(
       @JsonProperty("access_token") String accessToken) {
       this.accessToken = accessToken;
     }
   
     public String getAccessToken() {
       return accessToken;
     }
   
     @Override
     public String toString() {
       return "GithubTokenResponse{" +
           "accessToken='" + accessToken + '\'' +
           '}';
     }
   }

4. Change callback controller

   @GetMapping("/callback")
   @ResponseBody
   Object callback(@RequestParam String code) {
   
     GithubTokenResponse response = restTemplate.postForEntity("https://github.com/login/oauth/access_token?" +
         "client_id=13e67f9acf45a46a6567&" +
         "client_secret=dc51ddd68a03ff435a497b3023b44a37b55fbc1d&" +
         "code=" + code, null, GithubTokenResponse.class).getBody();
   
     return response;
   }

5. [Optional] Register your own oauth2 app https://github.com/settings/applications/new

   • upon successful registration you will get your own client_id and client_secret, change the above code to use your own app’s info