👷 gucc: add helper function to fetch file from url

.github/workflows/build.yml

@@ -42,6 +42,7 @@ jobs:
           ./gucc/tests/test-fstab_gen
           ./gucc/tests/test-crypttab_gen
           ./gucc/tests/test-grub_config_gen
+          ./gucc/tests/test-fetch_file
         shell: bash
   build-cmake_withoutdev:
     name: Build with CMake (DEVENV OFF)
@@ -90,6 +91,7 @@ jobs:
           ./gucc/tests/test-fstab_gen
           ./gucc/tests/test-crypttab_gen
           ./gucc/tests/test-grub_config_gen
+          ./gucc/tests/test-fetch_file
         shell: bash
   build-meson_withoutdev:
     name: Build with Meson (DEVENV OFF)

gucc/CMakeLists.txt

@@ -32,13 +32,14 @@ add_library(${PROJECT_NAME} #SHARED
    src/hwclock.cpp include/gucc/hwclock.hpp
    src/package_profiles.cpp include/gucc/package_profiles.hpp
    src/logger.cpp include/gucc/logger.hpp
+   src/fetch_file.cpp include/gucc/fetch_file.hpp
    #src/chwd_profiles.cpp src/chwd_profiles.hpp
    #src/disk.cpp src/disk.hpp
    )
 
 add_library(${PROJECT_NAME}::${PROJECT_NAME} ALIAS ${PROJECT_NAME})
 target_include_directories(${PROJECT_NAME} PUBLIC ${CMAKE_CURRENT_DIR}/include)
-target_link_libraries(${PROJECT_NAME} PUBLIC project_warnings project_options spdlog::spdlog fmt::fmt range-v3::range-v3 tomlplusplus::tomlplusplus)
+target_link_libraries(${PROJECT_NAME} PUBLIC project_warnings project_options spdlog::spdlog fmt::fmt range-v3::range-v3 tomlplusplus::tomlplusplus cpr::cpr)
 
 if(COS_INSTALLER_BUILD_TESTS)
    add_subdirectory(tests)

gucc/include/gucc/fetch_file.hpp

@@ -0,0 +1,15 @@
+#ifndef FETCH_FILE_HPP
+#define FETCH_FILE_HPP
+
+#include <optional>     // for optional
+#include <string>       // for string
+#include <string_view>  // for string_view
+
+namespace gucc::fetch {
+
+// Fetch file from url into memory
+auto fetch_file_from_url(std::string_view url, std::string_view fallback_url) noexcept -> std::optional<std::string>;
+
+}  // namespace gucc::fetch
+
+#endif  // FETCH_FILE_HPP

gucc/meson.build

@@ -22,6 +22,7 @@ gucc_lib = library('gucc',
         'src/hwclock.cpp',
         'src/package_profiles.cpp',
         'src/logger.cpp',
+        'src/fetch_file.cpp',
     ],
     include_directories : [include_directories('include')],
     dependencies: deps

gucc/src/fetch_file.cpp

@@ -0,0 +1,45 @@
+#include "gucc/fetch_file.hpp"
+
+#include <chrono>  // for chrono_literals
+
+#include <cpr/api.h>
+#include <cpr/response.h>
+#include <cpr/status_codes.h>
+#include <cpr/timeout.h>
+
+using namespace std::string_view_literals;
+
+namespace {
+
+auto fetch_file(std::string_view url) noexcept -> std::optional<std::string> {
+    using namespace std::chrono_literals;
+
+    auto timeout     = cpr::Timeout{30s};
+    auto response    = cpr::Get(cpr::Url{url}, timeout);
+    auto status_code = static_cast<std::int32_t>(response.status_code);
+
+    static constexpr auto FILE_URL_PREFIX = "file://"sv;
+    if (cpr::status::is_success(status_code) || (url.starts_with(FILE_URL_PREFIX) && status_code == 0 && !response.text.empty())) {
+        return std::make_optional<std::string>(std::move(response.text));
+    }
+    return std::nullopt;
+}
+
+}  // namespace
+
+namespace gucc::fetch {
+
+auto fetch_file_from_url(std::string_view url, std::string_view fallback_url) noexcept -> std::optional<std::string> {
+    auto fetch_content = fetch_file(url);
+    if (fetch_content) {
+        return std::make_optional<std::string>(std::move(*fetch_content));
+    }
+
+    fetch_content = fetch_file(fallback_url);
+    if (fetch_content) {
+        return std::make_optional<std::string>(std::move(*fetch_content));
+    }
+    return std::nullopt;
+}
+
+}  // namespace gucc::fetch

gucc/tests/CMakeLists.txt

@@ -4,7 +4,8 @@
 
 file(GLOB files unit-*.cpp)
 
-set(GUCC_TEST_DIR "${CMAKE_CURRENT_SOURCE_DIR}/")
+set(GUCC_TEST_DIR "${CMAKE_CURRENT_SOURCE_DIR}")
+set(GUCC_TOP_DIR "${CMAKE_SOURCE_DIR}")
 
 foreach(file ${files})
     get_filename_component(file_basename ${file} NAME_WE)
@@ -16,5 +17,6 @@ foreach(file ${files})
         $<$<CXX_COMPILER_ID:GNU>:-Wno-deprecated-declarations>
     )
     add_definitions(-DGUCC_TEST_DIR="${GUCC_TEST_DIR}")
+    add_definitions(-DGUCC_TOP_DIR="${GUCC_TOP_DIR}")
     target_link_libraries(${testcase} PRIVATE project_warnings project_options gucc::gucc)
 endforeach()

gucc/tests/meson.build

@@ -61,3 +61,11 @@ executable(
   link_with: [gucc_lib],
   include_directories: [include_directories('../include')],
   install: false)
+
+executable(
+  'test-fetch_file',
+  files('unit-fetch_file.cpp'),
+  dependencies: deps,
+  link_with: [gucc_lib],
+  include_directories: [include_directories('../include')],
+  install: false)

gucc/tests/unit-fetch_file.cpp

@@ -0,0 +1,45 @@
+#include "gucc/fetch_file.hpp"
+#include "gucc/file_utils.hpp"
+
+#include <cassert>
+
+#include <filesystem>
+#include <string_view>
+
+#include <fmt/format.h>
+
+namespace fs = std::filesystem;
+using namespace std::string_view_literals;
+
+int main() {
+    // existing remote url, non existent fallback url
+    static constexpr std::string_view LICENSE_PATH = GUCC_TOP_DIR "/LICENSE";
+    {
+        static constexpr auto remote_url = "https://github.com/CachyOS/New-Cli-Installer/raw/master/LICENSE"sv;
+
+        const auto& file_content = gucc::fetch::fetch_file_from_url(remote_url, "file:///ter-testunit");
+        assert(file_content);
+        assert(!file_content->empty());
+
+        const auto& expected_file_content = gucc::file_utils::read_whole_file(LICENSE_PATH);
+        assert(file_content == expected_file_content);
+    }
+    // non existent remote url, existing fallback url
+    {
+        static constexpr auto remote_url = "https://github.com/CachyOS/New-Cli-Installer/raw/master/LCNS"sv;
+
+        const auto& file_content = gucc::fetch::fetch_file_from_url(remote_url, fmt::format("file://{}", LICENSE_PATH));
+        assert(file_content);
+        assert(!file_content->empty());
+
+        const auto& expected_file_content = gucc::file_utils::read_whole_file(LICENSE_PATH);
+        assert(file_content == expected_file_content);
+    }
+    // non existent remote url, non existent fallback url
+    {
+        static constexpr auto remote_url = "https://github.com/CachyOS/New-Cli-Installer/raw/master/LCNS"sv;
+
+        const auto& file_content = gucc::fetch::fetch_file_from_url(remote_url, "file:///ter-testunit");
+        assert(!file_content);
+    }
+}

meson.build

@@ -55,6 +55,7 @@ add_global_arguments('-DINSTALLER_VERSION="' + git_version + '"', language : 'cp
 
 # gucc test path
 add_global_arguments('-DGUCC_TEST_DIR="' + meson.current_source_dir() + '/gucc/tests/"', language : 'cpp')
+add_global_arguments('-DGUCC_TOP_DIR="' + meson.current_source_dir() + '/"', language : 'cpp')
 
 # Common dependencies
 spdlog = dependency('spdlog', version : ['>=1.12.0'], fallback : ['spdlog', 'spdlog_dep'])