How to handle HTTP 403 forbidden error in Java

Sometimes when trying to connect to a web service using a java client, we may face a 403 forbidden HTTP response code, it is workable but in some reason the service is accessible normally from web browsers.

The HTTP 403 forbidden error doesn’t necessarily occur due to missing authentication attributes or invalid authentication, some web services would only authorize web browsers or some specific clients to access them, while they deny any requests coming from third-party clients. And we are going to handle this situation.

This problem is normally resolved by imitating the web browser request so that the web service deals with the java client as if it was a web browser.

Below is a typical request logged from a browser:

GET /feeds HTTP/1.1 Host: publicservice.com:443 Accept: */* Accept-Encoding: gzip, deflate, br Accept-Language: en-US,en;q=0.9 Cookie: OGP=-4061129:; SID=FAYIU7tO.... Referer: https://clients5.google.com/pagead/drt/dn/ User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36 X-Client-Data: CIa2yQEIpLbJAQjBtskBCKmdygEIqKPKARiSo8oB

As noticed, the “User-Agent” header specifies the name and the type of the client which is trying to access the service, so in order to imitate the web browser we need to add this header to our request. Following is how to add it using HttpUrlConnection:

String url = "https://xxx.com/yyy"; URL obj = new URL(url); HttpsURLConnection con = (HttpsURLConnection) obj.openConnection(); con.setRequestMethod("GET"); con.setRequestProperty("Content-Type", "application/json"); con.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36");