Deduplicate http header formatting and move to http file

include/cgimap/http.hpp

@@ -32,6 +32,8 @@ namespace http {
 
   using headers_t = std::vector<std::pair<std::string, std::string> >;
 
+  std::string format_header(int status, const headers_t &headers);
+
   /**
    * return a static string description for an HTTP status code.
    */

include/cgimap/output_buffer.hpp

@@ -1,11 +1,14 @@
 #ifndef OUTPUT_BUFFER_HPP
 #define OUTPUT_BUFFER_HPP
 
+#include <string_view>
+
 /**
  * Implement this interface to provide custom output.
  */
 struct output_buffer {
   virtual int write(const char *buffer, int len) = 0;
+  virtual int write(std::string_view str) { return write(str.data(), str.size()); }
   virtual int written() = 0;
   virtual int close() = 0;
   virtual void flush() = 0;

src/fcgi_request.cpp

@@ -121,14 +121,7 @@ void fcgi_request::set_current_time(const std::chrono::system_clock::time_point
 }
 
 void fcgi_request::write_header_info(int status, const http::headers_t &headers) {
-  std::ostringstream ostr;
-  ostr << "Status: " << status << " " << http::status_message(status) << "\r\n";
-  for (const auto& [name, value] : headers) {
-    ostr << name << ": " << value << "\r\n";
-  }
-  ostr << "\r\n";
-  std::string data(ostr.str());
-  m_buffer->write(&data[0], data.size());
+  m_buffer->write(http::format_header(status, headers));
 }
 
 output_buffer& fcgi_request::get_buffer_internal() {

src/http.cpp

@@ -102,6 +102,16 @@ const char *status_message(int code) {
   }
 }
 
+std::string format_header(int status, const headers_t &headers) {
+  std::string hdr{};
+  hdr += fmt::format("Status: {} {}\r\n", status, status_message(status));
+  for (const auto& [name, value] : headers) {
+    hdr += fmt::format("{}: {}\r\n", name, value);
+  }
+  hdr += "\r\n";
+  return hdr;
+}
+
 exception::exception(int c, string m)
     : code_(c), message_(std::move(m)) {}
 

test/test_request.cpp

@@ -78,15 +78,9 @@ void test_request::write_header_info(int status, const http::headers_t &headers)
   assert(m_output.tellp() == 0);
   m_status = status;
 
-  std::stringstream hdr;
-  hdr << "Status: " << status << " " << http::status_message(status) << "\r\n";
-  for (const auto& [name, value] : headers) {
-      hdr << name << ": " << value << "\r\n";
-  }
-  hdr << "\r\n";
-
-  m_output << hdr.str();
-  m_header << hdr.str();
+  auto hdr = http::format_header(status, headers);
+  m_output << hdr;
+  m_header << hdr;
 }
 
 int test_request::response_status() const {