http_examples.cpp

#include "server_http.hpp"
#include "client_http.hpp"

//Added for the json-example
#define BOOST_SPIRIT_THREADSAFE
#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/json_parser.hpp>

//Added for the default_resource example
#include <fstream>
#include <boost/filesystem.hpp>
#include <vector>
#include <algorithm>
#ifdef HAVE_OPENSSL
#include "crypto.hpp"
#endif

using namespace std;
//Added for the json-example:
using namespace boost::property_tree;

typedef SimpleWeb::Server<SimpleWeb::HTTP> HttpServer;
typedef SimpleWeb::Client<SimpleWeb::HTTP> HttpClient;

//Added for the default_resource example
void default_resource_send(const HttpServer &server, const shared_ptr<HttpServer::Response> &response,
                           const shared_ptr<ifstream> &ifs);

class MimeTypes {
    public:
        void load(const std::string &f);
        void parse(const std::string &mimestring);
        void parse(std::istream &mimestream);
        const std::string &lookup(const std::string &extension);
        std::unordered_map<std::string, std::string> _mime_db;
};

int main() {
    //HTTP-server at port 8080 using 1 thread
    //Unless you do more heavy non-threaded processing in the resources,
    //1 thread is usually faster than several threads
    HttpServer server;
    server.config.port=8080;
    
    // Mime Types
    MimeTypes mime_types;

    //Add resources using path-regex and method-string, and an anonymous function
    //POST-example for the path /string, responds the posted string
    server.resource["^/string$"]["POST"]=[](shared_ptr<HttpServer::Response> response, shared_ptr<HttpServer::Request> request) {
        //Retrieve string:
        auto content=request->content.string();
        //request->content.string() is a convenience function for:
        //stringstream ss;
        //ss << request->content.rdbuf();
        //string content=ss.str();
        
        *response << "HTTP/1.1 200 OK\r\nContent-Length: " << content.length() << "\r\n\r\n" << content;
    };
    
    //POST-example for the path /json, responds firstName+" "+lastName from the posted json
    //Responds with an appropriate error message if the posted json is not valid, or if firstName or lastName is missing
    //Example posted json:
    //{
    //  "firstName": "John",
    //  "lastName": "Smith",
    //  "age": 25
    //}
    server.resource["^/json$"]["POST"]=[](shared_ptr<HttpServer::Response> response, shared_ptr<HttpServer::Request> request) {
        try {
            ptree pt;
            read_json(request->content, pt);

            string name=pt.get<string>("firstName")+" "+pt.get<string>("lastName");

            *response << "HTTP/1.1 200 OK\r\n"
                      << "Content-Type: application/json\r\n"
                      << "Content-Length: " << name.length() << "\r\n\r\n"
                      << name;
        }
        catch(exception& e) {
            *response << "HTTP/1.1 400 Bad Request\r\nContent-Length: " << strlen(e.what()) << "\r\n\r\n" << e.what();
        }
    };

    //GET-example for the path /info
    //Responds with request-information
    server.resource["^/info$"]["GET"]=[](shared_ptr<HttpServer::Response> response, shared_ptr<HttpServer::Request> request) {
        stringstream content_stream;
        content_stream << "<h1>Request from " << request->remote_endpoint_address << " (" << request->remote_endpoint_port << ")</h1>";
        content_stream << request->method << " " << request->path << " HTTP/" << request->http_version << "<br>";
        for(auto& header: request->header) {
            content_stream << header.first << ": " << header.second << "<br>";
        }
        
        //find length of content_stream (length received using content_stream.tellp())
        content_stream.seekp(0, ios::end);
        
        *response <<  "HTTP/1.1 200 OK\r\nContent-Length: " << content_stream.tellp() << "\r\n\r\n" << content_stream.rdbuf();
    };
    
    //GET-example for the path /match/[number], responds with the matched string in path (number)
    //For instance a request GET /match/123 will receive: 123
    server.resource["^/match/([0-9]+)$"]["GET"]=[&server](shared_ptr<HttpServer::Response> response, shared_ptr<HttpServer::Request> request) {
        string number=request->path_match[1];
        *response << "HTTP/1.1 200 OK\r\nContent-Length: " << number.length() << "\r\n\r\n" << number;
    };
    
    //Get example simulating heavy work in a separate thread
    server.resource["^/work$"]["GET"]=[&server](shared_ptr<HttpServer::Response> response, shared_ptr<HttpServer::Request> /*request*/) {
        thread work_thread([response] {
            this_thread::sleep_for(chrono::seconds(5));
            string message="Work done";
            *response << "HTTP/1.1 200 OK\r\nContent-Length: " << message.length() << "\r\n\r\n" << message;
        });
        work_thread.detach();
    };
    
    //Default GET-example. If no other matches, this anonymous function will be called. 
    //Will respond with content in the web/-directory, and its subdirectories.
    //Default file: index.html
    //Can for instance be used to retrieve an HTML 5 client that uses REST-resources on this server
    server.default_resource["GET"]=[&server, &mime_types](shared_ptr<HttpServer::Response> response, shared_ptr<HttpServer::Request> request) {
        try {
            auto web_root_path=boost::filesystem::canonical("web");
            auto path=boost::filesystem::canonical(web_root_path/request->path);
            //Check if path is within web_root_path
            if(distance(web_root_path.begin(), web_root_path.end())>distance(path.begin(), path.end()) ||
               !equal(web_root_path.begin(), web_root_path.end(), path.begin()))
                throw invalid_argument("path must be within root path");
            if(boost::filesystem::is_directory(path))
                path/="index.html";
            if(!(boost::filesystem::exists(path) && boost::filesystem::is_regular_file(path)))
                throw invalid_argument("file does not exist");

            std::string cache_control, etag;

            // Uncomment the following line to enable Cache-Control
            // cache_control="Cache-Control: max-age=86400\r\n";

#ifdef HAVE_OPENSSL
            // Uncomment the following lines to enable ETag
            // {
            //     ifstream ifs(path.string(), ifstream::in | ios::binary);
            //     if(ifs) {
            //         auto hash=SimpleWeb::Crypto::to_hex_string(SimpleWeb::Crypto::md5(ifs));
            //         etag = "ETag: \""+hash+"\"\r\n";
            //         auto it=request->header.find("If-None-Match");
            //         if(it!=request->header.end()) {
            //             if(!it->second.empty() && it->second.compare(1, hash.size(), hash)==0) {
            //                 *response << "HTTP/1.1 304 Not Modified\r\n" << cache_control << etag << "\r\n\r\n";
            //                 return;
            //             }
            //         }
            //     }
            //     else
            //         throw invalid_argument("could not read file");
            // }
#endif

            auto ifs=make_shared<ifstream>();
            ifs->open(path.string(), ifstream::in | ios::binary | ios::ate);
            
            if(*ifs) {
                auto length=ifs->tellg();
                ifs->seekg(0, ios::beg);
                
                // Get the file extension and look up the corresponding mime type
                auto ext = path.filename().extension().string();
                if (!ext.empty() && ext[0] == '.') {
                    ext.erase(0, 1);
                }
                auto mime = mime_types.lookup(ext);
                std::string content_type;
                if (!mime.empty()) {
                    content_type = "Content-Type: " + mime + "\r\n";
                } // else if empty: Do not set Content-Type

                *response << "HTTP/1.1 200 OK\r\n" << cache_control << etag << content_type << "Content-Length: " << length  << "\r\n\r\n";
                default_resource_send(server, response, ifs);
            }
            else
                throw invalid_argument("could not read file");
        }
        catch(const exception &e) {
            string content="Could not open path "+request->path+": "+e.what();
            *response << "HTTP/1.1 400 Bad Request\r\nContent-Length: " << content.length() << "\r\n\r\n" << content;
        }
    };
    
    thread server_thread([&server](){
        //Start server
        server.start();
    });
    
    //Wait for server to start so that the client can connect
    this_thread::sleep_for(chrono::seconds(1));
    
    //Client examples

    // Load mime.types from Apache web site
    // If this site is not reachable or the response is not valid nothing will happen
    HttpClient apache_client("svn.apache.org");
    auto mr = apache_client.request("GET", "/repos/asf/httpd/httpd/trunk/docs/conf/mime.types");
   
    // Make sure we got a valid response
    if(mr->status_code == "200 OK") {
        mime_types.parse(mr->content);
    }

    HttpClient client("localhost:8080");
    auto r1=client.request("GET", "/match/123");
    cout << r1->content.rdbuf() << endl;

    string json_string="{\"firstName\": \"John\",\"lastName\": \"Smith\",\"age\": 25}";
    auto r2=client.request("POST", "/string", json_string);
    cout << r2->content.rdbuf() << endl;
    
    auto r3=client.request("POST", "/json", json_string);
    cout << r3->content.rdbuf() << endl;
    
    server_thread.join();
    
    return 0;
}

void default_resource_send(const HttpServer &server, const shared_ptr<HttpServer::Response> &response,
                           const shared_ptr<ifstream> &ifs) {
    //read and send 128 KB at a time
    static vector<char> buffer(131072); // Safe when server is running on one thread
    streamsize read_length;
    if((read_length=ifs->read(&buffer[0], buffer.size()).gcount())>0) {
        response->write(&buffer[0], read_length);
        if(read_length==static_cast<streamsize>(buffer.size())) {
            server.send(response, [&server, response, ifs](const boost::system::error_code &ec) {
                if(!ec)
                    default_resource_send(server, response, ifs);
                else
                    cerr << "Connection interrupted" << endl;
            });
        }
    }
}

/**
* Parses Apaches mime.types files
* @param path and file name to mime.types like file
*/
void MimeTypes::load(const std::string &f) {
   try {
       std::ifstream mimefile(f);
       if (mimefile.is_open()) {
           parse(mimefile);
       }
       mimefile.close();
   } catch (const std::exception &e) {
       // Something bad happened. How to handle this kind of exception?
       // Don't care for now
   }
}

void MimeTypes::parse(const std::string &mimestring) {
   std::stringstream mimestream(mimestring);
   parse(mimestream);
}

void MimeTypes::parse(std::istream &mimestream) {
   try {
       std::string line;
       while (std::getline(mimestream, line)) {

           // discard comments
           auto start_of_comment = line.find("#");
           if (start_of_comment != std::string::npos) {
               line.erase(start_of_comment, std::string::npos);
           }

           // mime type followed by zero or more file extensions
           std::istringstream iss(line);
           std::string mime;
           if (iss >> mime) {

               std::string ext;            // mime successful read
               while (iss >> ext) {        // read and insert extensions
                   if (!ext.empty()) {
                       _mime_db[ext] = mime;
                   }
               }
           }
       }
   } catch (const std::exception &e) {
       // Something bad happened. How to handle this kind of exception?
       // Don't care for now
   }
}

/**
* Looks up the Mime Type belonging to the File Extension
* @param file extension to look up
* @return Mime Type corresponding to extension. Or the empty string if nothing found. In case of "" do not set the Content Header!
*/
const std::string& MimeTypes::lookup(const std::string &extension) {
   auto finding = _mime_db.find(extension);

   if (finding != _mime_db.end()) {
       return (*finding).second;
   }

   static std::string unknown_mime_type = "";
   return unknown_mime_type;
}