initial commit

.clang-format

@@ -0,0 +1,52 @@
+---
+# BasedOnStyle:  LLVM
+AccessModifierOffset: -2
+ConstructorInitializerIndentWidth: 4
+AlignEscapedNewlinesLeft: false
+AlignTrailingComments: true
+AllowAllParametersOfDeclarationOnNextLine: true
+AllowShortBlocksOnASingleLine: false
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: None
+AlwaysBreakTemplateDeclarations: true
+AlwaysBreakBeforeMultilineStrings: false
+BreakBeforeBinaryOperators: true
+BreakBeforeTernaryOperators: true
+BreakConstructorInitializersBeforeComma: false
+BinPackParameters: true
+ColumnLimit:     80
+ConstructorInitializerAllOnOneLineOrOnePerLine: true
+DerivePointerAlignment: false
+ExperimentalAutoDetectBinPacking: false
+IndentCaseLabels: true
+IndentWrappedFunctionNames: false
+IndentFunctionDeclarationAfterType: true
+MaxEmptyLinesToKeep: 1
+KeepEmptyLinesAtTheStartOfBlocks: true
+NamespaceIndentation: None
+ObjCSpaceAfterProperty: false
+ObjCSpaceBeforeProtocolList: true
+PenaltyBreakBeforeFirstCallParameter: 19
+PenaltyBreakComment: 60
+PenaltyBreakString: 1000
+PenaltyBreakFirstLessLess: 120
+PenaltyExcessCharacter: 1000000
+PenaltyReturnTypeOnItsOwnLine: 60
+PointerAlignment: Left
+SpacesBeforeTrailingComments: 1
+Cpp11BracedListStyle: true
+Standard:        Cpp11
+IndentWidth:     4
+TabWidth:        8
+UseTab:          Never
+BreakBeforeBraces: Allman
+SpacesInParentheses: false
+SpacesInAngles:  false
+SpaceInEmptyParentheses: false
+SpacesInCStyleCastParentheses: false
+SpacesInContainerLiterals: true
+SpaceBeforeAssignmentOperators: true
+ContinuationIndentWidth: 4
+SpaceBeforeParens: ControlStatements
+...

.gitignore

@@ -0,0 +1 @@
+build/

CMakeLists.txt

@@ -0,0 +1,102 @@
+cmake_minimum_required(VERSION 3.0.0)
+project(meta-simple-http-server)
+
+set(CMAKE_EXPORT_COMPILE_COMMANDS 1)
+
+include(CTest)
+include(CheckCXXCompilerFlag)
+include_directories(include /usr/include /usr/local/include)
+
+option(USE_LIBCXX "Use libc++ for the C++ standard library" OFF)
+
+if(UNIX)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -pedantic")
+
+    # if we don't already set the standard for the compiler, detect the
+    # best one available and use it
+    if(NOT "${CMAKE_CXX_FLAGS}" MATCHES "std=c\\+\\+(11|1y|14)")
+        check_cxx_compiler_flag(-std=c++14 HAS_CXX14)
+        if(HAS_CXX14)
+            message("-- Compiler supports C++14 (using it)")
+            set(STDOPT "-std=c++14")
+        endif()
+
+        if(NOT STDOPT)
+            check_cxx_compiler_flag(-std=c++1y HAS_CXX1Y)
+            if(HAS_CXX1Y)
+                message("-- Compiler supports C++1y (using it)")
+                set(STDOPT "-std=c++1y")
+            endif()
+        endif()
+
+        if(NOT STDOPT)
+            check_cxx_compiler_flag(-std=c++11 HAS_CXX11)
+            if(HAS_CXX11)
+                message("-- Compiler supports C++11 (using it)")
+                set(STDOPT "-std=c++11")
+            endif()
+        endif()
+
+        if(NOT STDOPT)
+            message(FATAL_ERROR
+                "server requires a compiler with at least C++11 support")
+        endif()
+
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${STDOPT}")
+    endif()
+
+    if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+        if(CMAKE_GENERATOR STREQUAL "Ninja")
+          set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fdiagnostics-color")
+        endif()
+    endif()
+
+    if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+        if(CMAKE_GENERATOR STREQUAL "Ninja")
+          set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fcolor-diagnostics")
+        endif()
+        if(USE_LIBCXX)
+            message("-- Locating libc++...")
+            find_library(LIBCXX_LIBRARY NAMES c++ cxx)
+            if(LIBCXX_LIBRARY)
+                message("-- Located libc++, using it.")
+                set(LIBCXX_OPTIONS "-stdlib=libc++")
+                message("--     Locating libc++'s abi...")
+                find_library(LIBCXXABI_LIBRARY NAMES c++abi)
+                find_library(LIBCXXRT_LIBRARY NAMES cxxrt)
+                if(LIBCXXABI_LIBRARY)
+                    message("--     Found libc++abi, using it.")
+                    set(CXXABI_LIBRARY ${LIBCXXABI_LIBRARY})
+                elseif(LIBCXXRT_LIBRARY)
+                    message("--     Found libcxxrt, using it.")
+                    set(CXXABI_LIBRARY ${LIBCXXRT_LIBRARY})
+                else()
+                    message("--     No abi library found. "
+                            "Attempting to continue without one...")
+                endif()
+            endif()
+        else()
+            message("-- Could not find libc++, will not use it.")
+        endif()
+    endif()
+
+    find_library(LIBDL_LIBRARY NAMES dl ldl)
+    if(LIBDL_LIBRARY)
+      set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${LIBDL_LIBRARY}")
+    endif()
+
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${LIBCXX_OPTIONS}")
+    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${CXXABI_LIBRARY}")
+endif()
+
+find_library(LIBEVENT NAMES event)
+message("-- Found LIBEVENT: ${LIBEVENT}")
+
+find_package(Threads REQUIRED)
+
+add_library(simple-http-server src/simple_http_server.cpp)
+target_link_libraries(simple-http-server ${LIBEVENT} ${CMAKE_THREAD_LIBS_INIT})
+
+add_executable(api-server src/api_server.cpp)
+target_link_libraries(api-server simple-http-server ${LIBEVENT}
+    ${CMAKE_THREAD_LIBS_INIT})

README.md

@@ -0,0 +1,24 @@
+This class can be used to create simple demo APIs for various parts of
+[MeTA](https://meta-toolkit.org).
+
+It can also be used as a starting place for creating your own Web-based uses of
+MeTA.
+
+The implementation is based on [this blog
+post](http://kukuruku.co/hub/cpp/lightweight-http-server-in-less-than-40-lines-on-libevent-and-c-11).
+
+To test,
+
+```bash
+mkdir build
+cd build/
+cmake ../
+make
+./api-server
+```
+
+In another terminal,
+
+```bash
+curl --data "World" 0.0.0.0:8088
+```

include/simple_http_server.h

@@ -0,0 +1,61 @@
+/**
+ * @file simple_http_server.h
+ * @author Sean Massung
+ * @see
+ * http://kukuruku.co/hub/cpp/lightweight-http-server-in-less-than-40-lines-on-libevent-and-c-11
+ */
+
+#ifndef META_SIMPLE_HTTP_SERVER_H_
+#define META_SIMPLE_HTTP_SERVER_H_
+
+#include <event2/buffer.h>
+#include <evhttp.h>
+
+/**
+ * A very simple multithreaded HTTP server that can accept a string request and
+ * return a string response. Usually, the request and response will be JSON
+ * objects.
+ */
+class simple_http_server
+{
+  public:
+    /**
+     * @param on_request A function that is called for each request (which uses
+     * the context parameter to perform some operation)
+     * @param context A pointer to an object that performs an operation for each
+     * request
+     * @param address The address the server is running on
+     * @param port The port the server is running on
+     * @param num_threads Number of threads to listen for requests
+     */
+    simple_http_server(void (*on_request)(evhttp_request*, void*),
+                       void* context, const std::string& address = "0.0.0.0",
+                       int64_t port = 8088, int64_t num_threads = 4);
+
+    /**
+     * Starts the server and waits for a keypress to stop.
+     */
+    void start() const;
+
+    /**
+     * @param req The request "object" from libevent
+     * @return a std::string version of the request data from the client
+     */
+    static std::string receive_request_string(evhttp_request* req);
+
+    /**
+     * @param req The request "object" from libevent
+     * @param response The string data (probably JSON) to send to the client
+     */
+    static void send_response_string(evhttp_request* req,
+                                     const std::string& response);
+
+  private:
+    void (*on_request_)(evhttp_request*, void*);
+    void* context_;
+    std::string address_;
+    int64_t port_;
+    int64_t num_threads_;
+};
+
+#endif

src/api_server.cpp

@@ -0,0 +1,46 @@
+/**
+ * @file api_server.cpp
+ * @author Sean Massung
+ */
+
+#include <memory>
+#include <event2/buffer.h>
+#include <evhttp.h>
+
+#include "simple_http_server.h"
+
+class greeter
+{
+  public:
+    greeter(const std::string& greeting) : greeting_{greeting}
+    {
+        // nothing
+    }
+
+    std::string greet(const std::string& request) const
+    {
+        return greeting_ + " " + request + "\n";
+    }
+
+  private:
+    std::string greeting_;
+};
+
+int main()
+{
+    std::unique_ptr<greeter> grt = std::make_unique<greeter>("Hello");
+
+    void (*on_request)(evhttp_request*, void*)
+        = [](evhttp_request* req, void* void_ptr)
+    {
+        auto request_str = simple_http_server::receive_request_string(req);
+
+        greeter* grt_ptr = (greeter*)void_ptr;
+        auto result = grt_ptr->greet(request_str);
+
+        simple_http_server::send_response_string(req, result);
+    };
+
+    simple_http_server srv{on_request, grt.get()};
+    srv.start();
+}