Merge pull request #351 from scratchcpp/network

Add network API

Author: adazem009

CMakeLists.txt

@@ -8,6 +8,7 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(ZIP_SRC thirdparty/zip/src)
 
 option(LIBSCRATCHCPP_BUILD_UNIT_TESTS "Build unit tests" ON)
+option(LIBSCRATCHCPP_NETWORK_SUPPORT "Support for downloading projects" ON)
 
 find_package(nlohmann_json 3.9.1 REQUIRED)
 find_package(utf8cpp REQUIRED)
@@ -70,6 +71,15 @@ target_link_libraries(scratchcpp PRIVATE nlohmann_json::nlohmann_json)
 target_link_libraries(scratchcpp PRIVATE utf8cpp)
 target_link_libraries(scratchcpp PRIVATE zip)
 
+if (LIBSCRATCHCPP_NETWORK_SUPPORT)
+    include(FetchContent)
+    FetchContent_Declare(cpr GIT_REPOSITORY https://github.com/libcpr/cpr.git
+	                     GIT_TAG 3b15fa82ea74739b574d705fea44959b58142eb8) # 1.10.5
+    FetchContent_MakeAvailable(cpr)
+    target_link_libraries(scratchcpp PRIVATE cpr::cpr)
+    target_compile_definitions(scratchcpp PRIVATE LIBSCRATCHCPP_NETWORK_SUPPORT)
+endif()
+
 target_compile_definitions(scratchcpp PRIVATE LIBSCRATCHCPP_LIBRARY)
 
 if (LIBSCRATCHCPP_BUILD_UNIT_TESTS)

README.md

@@ -108,6 +108,11 @@ int main(int argc, char **argv) {
 }
 ```
 
+Loading projects from [scratch.mit.edu](https://scratch.mit.edu/) is supported too:
+```cpp
+libscratchcpp::Project p("https://scratch.mit.edu/projects/XXXXXX");
+```
+
 <!-- TODO: Add link to documentation -->
 
 <p align="right">(<a href="#readme-top">back to top</a>)</p>
@@ -139,7 +144,7 @@ int main(int argc, char **argv) {
 - [ ] Scratch 2.0 to 3.0 converter (help needed)
 - [ ] Scratch 1.4 and below to 3.0 converter (help needed)
 - [ ] API for comments
-- [ ] API for loading projects from URL
+- [x] API for loading projects from URL
 
 See the [open issues](https://github.com/scratchcpp/libscratchcpp/issues) for a full list of proposed features (and known issues).
 

include/scratchcpp/project.h

@@ -3,6 +3,7 @@
 #pragma once
 
 #include <memory>
+#include <functional>
 #include "spimpl.h"
 
 #include "global.h"
@@ -14,7 +15,11 @@ class ProjectPrivate;
 
 class IEngine;
 
-/*! \brief The Project class provides API for reading and running Scratch projects. */
+/*!
+ * \brief The Project class provides API for reading and running Scratch projects.
+ *
+ * \note Loading online projects is supported if the LIBSCRATCHCPP_NETWORK_SUPPORT option is set, just use setFileName("some URL")
+ */
 class LIBSCRATCHCPP_EXPORT Project
 {
     public:
@@ -37,6 +42,8 @@ class LIBSCRATCHCPP_EXPORT Project
 
         std::shared_ptr<IEngine> engine() const;
 
+        void setDownloadProgressCallback(const std::function<void(unsigned int, unsigned int)> &&f);
+
     private:
         spimpl::unique_impl_ptr<ProjectPrivate> impl;
 };

src/internal/CMakeLists.txt

@@ -6,4 +6,30 @@ target_sources(scratchcpp
     reader_common.h
     zipreader.cpp
     zipreader.h
+    projecturl.cpp
+    projecturl.h
+    idownloader.h
+    idownloaderfactory.h
+    iprojectdownloader.h
+    iprojectdownloaderfactory.h
+    projectdownloaderfactory.cpp
+    projectdownloaderfactory.h
 )
+
+if (LIBSCRATCHCPP_NETWORK_SUPPORT)
+    target_sources(scratchcpp
+      PRIVATE
+        downloader.cpp
+	downloader.h
+	downloaderfactory.cpp
+	downloaderfactory.h
+	projectdownloader.cpp
+	projectdownloader.h
+    )
+else()
+    target_sources(scratchcpp
+      PRIVATE
+        projectdownloaderstub.cpp
+	projectdownloaderstub.h
+)
+endif()

src/internal/downloader.cpp

@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#include <iostream>
+
+#include "downloader.h"
+
+using namespace libscratchcpp;
+
+Downloader::Downloader()
+{
+    m_session.SetTimeout(cpr::Timeout(5000));
+}
+
+bool Downloader::download(const std::string &url)
+{
+    m_session.SetUrl(cpr::Url(url));
+    m_response = m_session.Get();
+
+    if (m_response.status_code != 200) {
+        std::cerr << "download error: " << m_response.error.message << std::endl;
+
+        if (m_response.status_code != 0)
+            std::cerr << "code: " << m_response.status_code << std::endl;
+
+        std::cerr << "URL: " << url << std::endl;
+        return false;
+    }
+
+    return true;
+}
+
+const std::string &Downloader::text() const
+{
+    return m_response.text;
+}

src/internal/downloader.h

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <cpr/api.h>
+#include <cpr/response.h>
+
+#include "idownloader.h"
+
+namespace libscratchcpp
+{
+
+class Downloader : public IDownloader
+{
+    public:
+        Downloader();
+
+        bool download(const std::string &url) override;
+        const std::string &text() const override;
+
+    private:
+        cpr::Session m_session;
+        cpr::Response m_response;
+};
+
+} // namespace libscratchcpp

src/internal/downloaderfactory.cpp

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#include "downloaderfactory.h"
+#include "downloader.h"
+
+using namespace libscratchcpp;
+
+std::shared_ptr<DownloaderFactory> DownloaderFactory::m_instance = std::make_shared<DownloaderFactory>();
+
+DownloaderFactory::DownloaderFactory()
+{
+}
+
+std::shared_ptr<DownloaderFactory> DownloaderFactory::instance()
+{
+    return m_instance;
+}
+
+std::shared_ptr<IDownloader> DownloaderFactory::create() const
+{
+    return std::make_shared<Downloader>();
+}

src/internal/downloaderfactory.h

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include "idownloaderfactory.h"
+
+namespace libscratchcpp
+{
+
+class DownloaderFactory : public IDownloaderFactory
+{
+    public:
+        DownloaderFactory();
+
+        static std::shared_ptr<DownloaderFactory> instance();
+        std::shared_ptr<IDownloader> create() const override;
+
+    private:
+        static std::shared_ptr<DownloaderFactory> m_instance;
+};
+
+} // namespace libscratchcpp

src/internal/idownloader.h

@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <string>
+
+namespace libscratchcpp
+{
+
+class IDownloader
+{
+    public:
+        virtual ~IDownloader() { }
+
+        virtual bool download(const std::string &url) = 0;
+        virtual const std::string &text() const = 0;
+};
+
+} // namespace libscratchcpp

src/internal/idownloaderfactory.h

@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <memory>
+
+namespace libscratchcpp
+{
+
+class IDownloader;
+
+class IDownloaderFactory
+{
+    public:
+        virtual ~IDownloaderFactory() { }
+
+        virtual std::shared_ptr<IDownloader> create() const = 0;
+};
+
+} // namespace libscratchcpp