How to get expand=changelog by API calls from JIRA server via Java

[Kaan Emek]

Hi everyone, 

We are trying to save all the changelog (String) via expand of all issues. Where we itterate trough all issues in Java.

We are using JIRA sever. In the browser I can open the page:
'.../rest/api/issue/{key}?expand=changelog'

The main goal of this approach is, to get the transitions of the different status exp. 

"created": "2022-05-11T08:14:34.000+0200",
"items": [
{
"field": "status",
"fieldtype": "jira",
"from": "1",
"fromString": "Open",
"to": "3",
"toString": "In Progress"
}
] 

 If i try it with this code:

public static String urlReader(String theUrl) // .../rest/api/issue/{key}?expand=changelog
{
    StringBuilder content = new StringBuilder();
    // Use try and catch to avoid the exceptions
    try
    {
        URL url = new URL(theUrl); // creating a url object
        URLConnection urlConnection = url.openConnection(); // creating a urlconnection object

        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
        String line;

        while ((line = bufferedReader.readLine()) != null)
        {
            content.append(line + "\n");
        }
        bufferedReader.close();
    }
    catch(Exception e)
    {
        e.printStackTrace();
    }
    System.out.println(content.toString());
    return content.toString();
}

Im getting this error: Server returned HTTP response code: 401 for URL:

---

Do someone know how to solve this problem?

Thanks

[Radek Dostál]

Well, 401 means Unauthorized (https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/401), so your problem is not in the code, but rather that the HTTP request you are sending does not contain any credentials.

You need to set an 'Authorization: <value>' header on the request. Ideally a PAT: https://confluence.atlassian.com/enterprise/using-personal-access-tokens-1026032365.html

I don't know if you can set headers on URLConnection, I don't use this and never have, but here's one example of authorization header with HttpClient which I use in my scripts:

import com.atlassian.jira.component.ComponentAccessor
import org.apache.http.HttpEntity
import org.apache.http.HttpHeaders
import org.apache.http.client.methods.CloseableHttpResponse
import org.apache.http.client.methods.HttpGet
import org.apache.http.impl.client.CloseableHttpClient
import org.apache.http.impl.client.HttpClientBuilder
import org.apache.http.util.EntityUtils

//either can use this for dynamical base url, or just hardcode it
final String BASE_URL = ComponentAccessor.getApplicationProperties().getString("jira.baseurl")

//this is our http client we will use to execute http requests
CloseableHttpClient closeableHttpClient = HttpClientBuilder.create().build()

//HttpGet, HttpPost, etc., whatever it is we are doing
HttpGet httpGet = new HttpGet(BASE_URL + "/whatever/rest/endpoint/I/want")

//Set the authorization header
//If you don't have PAT, you can do "Basic user:pwd" but it's a really bad practice, use PAT
//Alternatively you can also provide a JSESSIONID cookie instead of a header
httpGet.setHeader(HttpHeaders.AUTHORIZATION, "Bearer <personal access token>")

//Execute the http request via our client
CloseableHttpResponse closeableHttpResponse = closeableHttpClient.execute(httpGet)

//Do something with the response
int statusCode = closeableHttpResponse.getStatusLine().getStatusCode()
HttpEntity entity = closeableHttpResponse.getEntity()
String responseString = entity != null ? EntityUtils.toString(entity) : null

//Close the response
closeableHttpResponse.close()

//Finally close the http client when we're done
closeableHttpClient.close()

[Kaan Emek]

Thank you for your help. I cant test it. i cant import 

import com.atlassian.jira.component.ComponentAccessor

do you have any idea how i can import it? maybe a maven dependency ?

thanks

[Radek Dostál]

Oh, you're actually using java outside Jira, not groovy, interesting.

So then just remove the component accessor. The only thing it does in my example is getting Jira's baseurl.