allow requesting file type, try to guess right quality

src/image.cpp

@@ -71,7 +71,25 @@ void write(Magick::Image &img,
            const std::optional<std::string_view> magick_force) {
     std::string magick{magick_force.value_or(img.magick())};
     std::transform(magick.begin(), magick.end(), magick.begin(), ::tolower);
+
+    const auto quality{[&img, &magick]() -> size_t {
+        if (img.quality() != 0) {
+            return img.quality(); // same as source
+        }
+        if (magick == "png") {
+            return 100; // highest compression
+        }
+        if (magick == "webp") {
+            if (img.magick() == "WEBP" || img.magick() == "PNG"
+                || img.magick() == "GIF" || img.magick() == "SVG") {
+                return 100; // lossless
+            }
+        }
+        return 0; // default
+    }()};
+
     img.magick(magick);
+    img.quality(quality);
 
     Magick::Blob buffer;
     img.write(&buffer);

src/image.hpp

@@ -34,7 +34,7 @@ namespace libravatarserv::image {
 
 // write image with headers to stdout
 void write(Magick::Image &img,
-           std::optional<std::string_view> magick_force = nullptr);
+           std::optional<std::string_view> magick_force = {});
 
 } // namespace libravatarserv::image
 

src/request.cpp

@@ -20,6 +20,7 @@
 #include "types.hpp"
 
 #include <algorithm>
+#include <array>
 #include <cstdint>
 #include <iostream>
 #include <stdexcept>
@@ -47,6 +48,25 @@ request_t parse(const std::string_view uri) {
     std::transform(uri.begin() + offset, uri.begin() + pos, req.hash.begin(),
                    ::tolower);
 
+    if (const auto pos_dot{req.hash.find('.')}; pos_dot != std::string::npos) {
+        std::string magick{req.hash.substr(pos_dot + 1)};
+        req.hash = req.hash.substr(0, pos_dot);
+
+        if (magick == "jpg") {
+            magick = "jpeg";
+        }
+        constexpr std::array<std::string_view, 4> allowed{
+            {"jpeg", "png", "gif", "webp"}
+        };
+        if (std::any_of(allowed.begin(), allowed.end(),
+                        [magick](const std::string_view supplied) {
+                            return magick == supplied;
+                        })) {
+            req.magick = magick;
+        }
+    }
+    std::cout << req.hash << " - " << req.magick << '\n';
+
     if (req.hash.size() == 64 && hash::is_valid(req.hash)) {
         req.algo = algorithm_t::SHA256;
     } else if (req.hash.size() == 32 && hash::is_valid(req.hash)) {

src/types.hpp

@@ -31,6 +31,7 @@ struct request_t {
     algorithm_t algo;
     std::int16_t size;
     std::string fallback;
+    std::string magick;
 };
 
 } // namespace libravatarserv