lpcvoid · December 26, 2022 14:16 · Dec 26, 2022
diff --git a/http.hpp b/http.hpp
@@ -0,0 +1,84 @@
+#pragma once
+
+namespace netlib::http {
+
+using http_header_entry = std::pair<std::string, std::string>;
+using http_headers = std::vector<http_header_entry>;
+
+struct http_response {
+    http_headers headers;
+    uint32_t response_code;
+    std::pair<uint32_t, uint32_t> version;
+    std::string body;
+    inline std::error_condition from_raw_response(const std::string& raw_response) {
+        // a very rudimentary http response parser
+        if (raw_response.empty()) {
+            return std::errc::no_message;
+        }
+
+        /* strategy:
+         * split into multiple (at least two) parts, delimited by \r\n\r\n"
+         * within the first part:
+         *      first, parse the status line
+         *      second, parse the header fields, until we arrive at an empty line (only CR LF)
+         *      last, an optional body
+         * then, for the rest of the parts, concat into body
+         */
+
+        auto split = [](const std::string& str, const std::string& delimiter) -> std::vector<std::string> {
+            std::vector<std::string> split_tokens;
+            std::size_t start;
+            std::size_t end = 0;
+            while ((start = str.find_first_not_of(delimiter, end)) != std::string::npos)
+            {
+                end = str.find(delimiter, start);
+                split_tokens.push_back(str.substr(start, end - start));
+            }
+            return split_tokens;
+        };
+
+        std::vector<std::string> header_body_split = split(raw_response, "\r\n\r\n");
+        //split header part of response into response_header_lines
+        std::vector<std::string> response_header_lines = split(header_body_split.front(), "\r\n");
+        //first line should start with "HTTP"
+        if (!response_header_lines.front().starts_with("HTTP")) {
+            return std::errc::result_out_of_range;
+        }
+        //attempt to parse status line
+        //split into parts by space
+        auto status_parts = split(response_header_lines.front(), " ");
+        if (status_parts.size() < 3) {
+            return std::errc::bad_message;
+        }
+        //parse "HTTP/x.x"
+        auto version_parts = split(status_parts.front(), "/");
+        if (version_parts.size() != 2) {
+            return std::errc::bad_message;
+        }
+        //parse "x.x"
+        auto version_components = split(version_parts.back(), ".");
+        version.first = std::stoi(version_components.front());
+        version.second = std::stoi(version_components.back());
+        //parse response code
+        response_code = std::stoi(status_parts[1]);
+        //there can be an optional code description in the first line, but we ignore that here
+        //parse the response header lines until the end
+        //start at second line, first is status
+        std::for_each(response_header_lines.begin(), response_header_lines.end(), [&](const std::string& header_component){
+            auto component_parts = split(header_component, ":");
+            if (component_parts.size() == 2) {
+                headers.emplace_back(component_parts.front(), component_parts.back());
+            }
+        });
+
+        //now, take the body part(s) and concat them
+        std::for_each(header_body_split.begin() + 1, header_body_split.end(), [&](const std::string& body_line){
+            body += body_line;
+        });
+
+        return {};
+
+    };
+};
+
+}