[JAVA] Get account information by accessing Strava's API
Introduction
Strava has an API! But there is no Japanese document! It's hard to understand! I had a hard time in this situation, so I would like to keep a record for the athlete engineer. Let's exercise together and code with a healthy body! !!
What is Strava
This is an SNS for athletes. You can record various activities such as running, biking, and swimming. In strava, API for developersが提供されており、このAPIを使うことでアスリート情報や登録してある自転車やシューズの情報を取得できます。
Content of this article
It describes how to register the app on Strava and make an HTTP request to get the bicycle information. GET? POST? what is that? I made it from such a state, so I think that the content is easy to understand even for beginners.
Development environment
Especially this time, I think that it does not depend on the development environment, but I will describe it for the time being.
- OS:mac OS HighSierra
- Eclipse4.8
- Tomcat 9.0.26
- JDK 1.8.0
Register your app on Strava
First, log in to strava and go to the settings page under My API Application ( https://developers.strava.com/)アクセスすると自分のアプリを登録することができます。
At this point, it's okay if you don't have a separate app, so let's register appropriately. For the time being the website
http://127.0.0.1:8080
will do. : 8080 is set to 8080 because I intended to make an application using tomcat. (8080 is the port number used by tomcat.)
Authentication callback domain too
127.0.0.1:8080
I will leave it as.
If you register the icon properly, the client ID, client sheet, and other values will be given.
Access Web API
There are two main tasks.
- Get the access token needed to hit the Web API.
- Then use the token to access the Web API and get the information.
1. Obtaining an access token
Strava has introduced a mechanism called Oauth 2.0. Regarding Oauth, the following Qiita article was very easy to understand, so please refer to this. The most easy-to-understand explanation of OAuth
Basically strava's official documentation Will be followed.
In order to get the token, add the header information to the following URL and use the GET method to skip the HTTP request.
https://www.strava.com/oauth/mobile/authorize
When adding information in the GET method, add it after the URL. The following five pieces of information are required to obtain the token this time.
-
clientid This is the value of the client ID that was displayed when you registered the app on Strava earlier.
-
redirect_uri Gives the URL to redirect to after authentication is complete. ** Note: The request will fail if it is not included in the domain of this redirect URL and the authentication callback domain when you registered your app on Strava ** So in this case the redirect_uri domain should also be 127.0.0.1.
-
response_type This value is always ** code **.
-
approval_prompt Select either ** force ** or ** auto **. ** force **: Authentication is performed every time. ** auto **: Once authenticated, it will be automatically authenticated for a while (?).
-
scope You can decide the range of access to user information. Since various things such as ** read **, ** read_all **, ** profile: read_all ** are prepared Choose the one that suits what you want to do with your app.
As an example, the URL with the header added looks like this:
https://www.strava.com/oauth/authorize?client_id=****&response_type=code&redirect_uri=http://127.0.0.1:8080/hoge&scope=read&approval_prompt=auto
When you access this URL, you will see the following screen.
If you press Allow here, you will be taken to the Strava login screen, and when you log in, you will be authenticated and you will be taken to the redirect URL. I think that the URL of the redirect destination contains the part "code =".
hogehoge/state=&code=hogehogehogehoge&scope....
** Make a note of the value in this code as it will be used. ** **
Next, make an HTTP request to the following URL using the POST method.
https://www.strava.com/oauth/token
You can get an access token by giving the necessary information to the body of this POST method. The following 5 pieces of information are given to the body.
-
clientID The value of the client ID given when you registered the app on Strava
-
client_secret Client sheet value given when registering the app on Strava (Error in client secret?)
-
code The value of the code included in the URL of the redirect destination earlier
-
grant_type Be sure to use ** authorization_code **. I think that the implementation of the POST method differs depending on the environment in which the application is implemented, but in the case of Java, it was implemented in the following form.
request_token.java
URL url = new URL("https://www.strava.com/oauth/token");
HttpURLConnection con = (HttpURLConnection)url.openConnection();
con.setRequestMethod("POST");
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
con.setDoOutput(true);
con.setDoInput(true);
con.connect();
String body = "client_id=****&client_secret=****&code=****&grant_type=authorization_code";
byte[] postData = body.getBytes(StandardCharsets.UTF_8);
try(DataOutputStream outputStream = new DataOutputStream(con.getOutputStream())){
outputStream.write(postData);
}
Then, ** access_token ** exists in the response to this request, so get this token. The sample code looks like the following.
gettoken.java
String responseData = "";
InputStream stream = con.getInputStream();
StringBuffer sb = new StringBuffer();
String line = "";
BufferedReader br = new BufferedReader(new InputStreamReader(stream, "UTF-8"));
while((line = br.readLine()) != null) {
sb.append(line);
}
try {
stream.close();
}catch(Exception e) {
e.printStackTrace();
}
responseData = sb.toString();
con.disconnect();
JSONObject json = new JSONObject(responseData);
String token = json.getString("access_token");
2. Get information
I would like to actually get bicycle information using the access token I got earlier. In order to get the bicycle information, if you get the athlete information, it seems that it is written in it, so I will try to get the athlete information.
According to the official documentation (https://developers.strava.com/docs/reference/#api-Athletes)
https://www.strava.com/api/v3/athlete
On the other hand, it says that if you give token to the property and GET it, a response will be returned, so I will try it as told.
The sample code looks like the following. Don't forget to prefix the token with "Bearer".
getathlete.java
url = new URL("https://www.strava.com/api/v3/athlete");
HttpURLConnection con = (HttpURLConnection)url.openConnection();
con.setRequestMethod("GET");
String authorization = "Bearer " + token; //token is the value of token obtained earlier
con.setRequestProperty("Authorization", authorization);
con.setDoOutput(false);
con.setDoInput(true);
con.connect();
responseData = "";
stream = con.getInputStream();
sb = new StringBuffer();
line = "";
br = new BufferedReader(new InputStreamReader(stream, "UTF-8"));
while((line = br.readLine()) != null) {
sb.append(line);
}
try {
stream.close();
}catch(Exception e) {
e.printStackTrace();
}
responseData = sb.toString();
con.disconnect();
json = new JSONObject(responseData);
As you can see from the official document, the bicycle information has a nested structure of an array called bike []. In such a case, you need to get it using jsonarray etc.
getbikes.java
JSONArray BIKE = json.getJSONArray("bikes");
int distance = BIKE.getJSONObject(Integer.parseInt(0)).getInt("distance");
String bikeid = BIKE.getJSONObject(Integer.parseInt(0)).getString("id");
String bikename = BIKE.getJSONObject(Integer.parseInt(0)).getString("name");
Finally
I wrote a series of flow to get information by hitting API after registering the application on Strava. I think that it depends on the implementation environment depending on the requested part, but isn't the general flow the same? Let's use Strava's API well and exercise efficiently!
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