implement HTTP redirects. That's what the URL parser is necessary at all. :-)

webclient.cc

@@ -1,4 +1,5 @@
 #include "webclient.hh"
+#include "url_parser.hh"
 
 #include <string>
 #include <stdexcept>
@@ -24,8 +25,29 @@ using tcp = net::ip::tcp;           // from <boost/asio/ip/tcp.hpp>
 namespace
 {
 
+std::string redirect(boost::string_view url_string, int redirection_level)
+{
+    const pEp::URL url = pEp::parse_url(url_string.data(), url_string.data()+url_string.size());
+    
+    if(!url.username.empty() || !url.password.empty())
+    {
+        throw pEp::HttpError(901, "Redirect to URL with username:password is not supported.");
+    }
+    
+    const bool secure = (
+        url.schema=="https" ? true :
+            (url.schema=="http" ? false :
+                throw pEp::HttpError(902, "Unknown URL schema \"" + url.schema + "\"")
+            )
+        );
+    
+    pEp::Webclient client{url.host, secure, url.port};
+    return client.get(url.path_and_query, redirection_level);
+}
+
+
 template<class Stream>
-std::string fetch_and_close(Stream& stream, const std::string& server, const std::string& url)
+std::string fetch_and_close(Stream& stream, const std::string& server, const std::string& url, int redirection_level)
 {
     // Set up an HTTP GET request message
     http::request<http::string_body> req{http::verb::get, url, 11};
@@ -43,9 +65,27 @@ std::string fetch_and_close(Stream& stream, const std::string& server, const std
     
     // Receive the HTTP response
     http::read(stream, buffer, res);
-
     
-    return boost::beast::buffers_to_string(res.body().data());
+    switch(res.result())
+    {
+        case http::status::ok :
+        case http::status::no_content: return boost::beast::buffers_to_string(res.body().data());
+        
+        case http::status::moved_permanently:
+        case http::status::found: // was "moved temporarily"
+        case http::status::see_other:
+        case http::status::temporary_redirect:
+        case http::status::permanent_redirect:
+            if(redirection_level < pEp::MaxRedirectionLevel)
+            {
+                return redirect(res["Location"], redirection_level + 1);
+            } else {
+                throw pEp::HttpError(900, "Too many redirections!");
+            }
+        
+        default: // HTTP error or unknown/not implemented response code.
+            throw pEp::HttpError(res.result_int(), boost::beast::buffers_to_string(res.body().data() ));
+    }
 }
 
 } // end of anonymous namespace
@@ -57,7 +97,7 @@ HttpError::HttpError(unsigned error_code, const std::string& error_message)
 
 
 // based on https://www.boost.org/doc/libs/1_75_0/libs/beast/doc/html/beast/quick_start/http_client.html
-std::string Webclient::get(const std::string& url)
+std::string Webclient::get(const std::string& url, int redirection_level)
 {
     std::string ret;
     
@@ -95,7 +135,7 @@ std::string Webclient::get(const std::string& url)
         
         // Perform the SSL handshake
         stream.handshake(ssl::stream_base::client);
-        ret = fetch_and_close(stream, m_server_name, url);
+        ret = fetch_and_close(stream, m_server_name, url, redirection_level);
 
         // Gracefully close the socket
         beast::error_code ec;
@@ -113,7 +153,7 @@ std::string Webclient::get(const std::string& url)
     
         // Make the connection on the IP address we get from a lookup
         stream.connect(results);
-        ret = fetch_and_close(stream, m_server_name, url);
+        ret = fetch_and_close(stream, m_server_name, url, redirection_level);
 
         // Gracefully close the socket
         beast::error_code ec;

webclient.hh

@@ -5,6 +5,9 @@
 
 namespace pEp
 {
+    // to avoid infinite redirection loops
+    enum { MaxRedirectionLevel = 23 };
+
     class HttpError : public std::runtime_error
     {
     public:
@@ -21,7 +24,7 @@ namespace pEp
         , m_port{port==0 ? (secure?443:80) : port}
         {}
         
-        std::string get(const std::string& url);
+        std::string get(const std::string& url, int redirection_level = 0);
     
     private:
         const std::string& m_server_name;