Headers lost when recieving headers with same key #158

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1. KaiPetzke commented on Aug 17, 2020

   

   KaiPetzke

   on Aug 17, 2020

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   I agree with ElonDusk, that changing HeaderField from std::map to std::multimap would be a good idea. That std::multimap should use the same caseless sorting, that I have already proposed in #157

   Unfortunately, changing to multimap is going to break code, that already uses this library, as std::map::at() and std::map::operator[], which are commonly used to search for header fields, have no counterparts in std::multimap. Instead, std::multimap::find() and std::multimap::equal_range() need to be used now, which makes code more lengthy. So this old code:

   RestClient::Response& r = conn->get("/URL");
   std::string& ctype = r.headers["Content-Type"];
   std::string& clength = r.headers["Content-Length"];
   

   now becomes something ugly like this:

   RestClient::Response& r = conn->get("/URL");
   std::string ctype, clength;
   if(auto hdrit = r.headers.find("Content-Type"); hdrit != r.headers.end()) {
       ctype = hdrit->second;
   }
   if(auto hdrit = r.headers.find("Content-Length"); hdrit != r.headers.end()) {
       clength = hdrit->second;
   }
   

   On the other hand, the library user would now be able to iterate over all Cookies received:

   for(auto [rbegin, rend] = r.headers.equal_range("Set-Cookie"); rbegin != rend; rbegin++) {
       std::cout << "Cookie received: " << rbegin->second << std::endl;
   }
   

   Suggestion

   • Add a new field fullheaders to RestClient::Info and RestClient::Response, which is a case-insensitive multimap.
   • Replace RestClient::Info::headers and RestClient::Response::headers with a proxy class, that offers operator [] and the method at() with the old style behaviour (find the last match only) for compatibility for old programs.
   • Add a convenience method RestClient::Response::GetHeader(const std::string& name), which returns the last header named name. It throws std::out_of_range, if no matching header can be found.
   • Add a convenience method RestClient::Response::GetHeader(const std::string& name, const std::string& dflt), which returns the last header named name, or dflt, if no such header can be found.

   Any further suggestions?
2. edwinpjacques commented on Oct 30, 2020

   

   edwinpjacques

   on Oct 30, 2020

   Contributor

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   @ElonDusk26 and @KaiPetzke maybe the two of you could work together on that change?