Henry Leinen / HTTPServer

Single instance HTTP Server using new Ethernet Interface.

Dependents:   EthHTTPServer if201410_section5 _PE2E_12-04_EthernetInterfaceServer MGAS_GR_Peach ... more

Fork of WiFlyHTTPServer by Henry Leinen

Desciprtion of the library

Overview

This is an HTTPServer library using the new MBED EthernetInterface library. It allows you to :

  • serve files from any file System
  • use Remote procedure calls
  • extend the HTTPServer functionality according to your needs, using the provided handler classes or writing new classes. The following sections will give you a brief overview of how to use the library.

Usage description

You can use the library as file server, as RPC server or a combination of both. You can even define your own behaviour by deriving from one of the classes provided.

Use as file server

You may want to look at my sample application which allows you to serve files from the internal local storage of the mbed with no modifcation of the code :

Very simple example application

#include "mbed.h"
#include "HTTPServer.h"
#include "FsHandler.h"
#include "LocalFileSystem.h"

//  Use LED1 to indicate that the main loop is still executing
DigitalOut myled(LED1);
//  Use the serial connection 'pc' to dump debug information
Serial pc(USBTX, USBRX, "pc");
//  Instantiate a HTTPServer to handle incoming requests
HTTPServer  svr;
//  Instantiate a local file system handler named 'local' which will be used later to access files on the mbed.
LocalFileSystem local("local");


int main() {

    pc.baud(460800);
    HTTPFsRequestHandler::mount("/local/", "/");
    svr.addHandler<HTTPFsRequestHandler>("/");

    if (!svr.start()) {
       error("Server not starting !");
        exit(0);
    }
    
    while(1) {
        svr.poll();
        myled = 1;
        wait(0.2);
        myled = 0;
        wait(0.2);
    }
}

Another alternative is to provide the EthernetInterface library to the HTTPServer library. This may be useful in case you need to perform other tasks with your internet connection. In this case it is necessary that you initialize the EthernetInterface and perform the connection prior to calling the start() method. Here is the example :

Sample application with re-use of existing EthernetInterface object

#include "mbed.h"
#include "HTTPServer.h"
#include "FsHandler.h"
#include "LocalFileSystem.h"
#include "EthernetInterface.h"


//  Use LED1 to indicate that the main loop is still executing
DigitalOut myled(LED1);
//  Use the serial connection 'pc' to dump debug information
Serial pc(USBTX, USBRX, "pc");
//  Instantiate a HTTPServer to handle incoming requests
HTTPServer  svr;
//  Instantiate a local file system handler named 'local' which will be used later to access files on the mbed.
LocalFileSystem local("local");
//  Create the EthernetInterface. This is optional, please see the documentation of HTTP Server's start method.
EthernetInterface eth;


int main() {

    pc.baud(460800);
    HTTPFsRequestHandler::mount("/local/", "/");
    svr.addHandler<HTTPFsRequestHandler>("/");

    //  Initialize the EthernetInterface and initiate a connection using DHCP.
    eth.init();
    eth.connect();

    // ***
    // TODO: Perform other Tasks using the ethernet connection here.
    // ****
    
    // Now start the server on port 80.
    if (!svr.start(80, &eth)) {
        error("Server not starting !");
        exit(0);
    }
    
    // The whole server activity is performed in this Loop. You can also put it into a separate RTOS Task and let it run there all the time.
    while(1) {
        svr.poll();
        myled = 1;
        wait(0.2);
        myled = 0;
        wait(0.2);
    }
}

Use as remote procedure call (RPC) server

To access objects or resources via HTTP you can make use of the RPC functionality. Each object that shall be accessible via HTTP needs to be registered before use. Here is an example which Registers the DigitalOut class for use over RPC :

RPC usage over HTTPServer

#include "mbed.h"
#include "HTTPServer.h"
#include "RpcHandler.h"
#include "mbed_rpc.h"

//  Use LED1 to indicate that the main loop is still executing
DigitalOut myled(LED1);
//  Use the serial connection 'pc' to dump debug information
Serial pc(USBTX, USBRX, "pc");
//  Instantiate a HTTPServer to handle incoming requests
HTTPServer  svr;


int main() {

    pc.baud(460800);
    RPC::add_rpc_class<RpcDigitalOut>();
    svr.addHandler<HTTPRpcRequestHandler>("/RPC");
    
    if (!svr.start()) {
        error("Server not starting !");
        exit(0);
    }
    
    while(1) {
        svr.poll();
        myled = 1;
        wait(0.2);
        myled = 0;
        wait(0.2);
    }
}

And using the above code, enter the following in the address field of your browser :

http://<your_mbed_ip>/RPC/DigitalOut/new LED4 myled4 - - > to create a new object of type DigitalOut on pin LED4 which can be referred to as 'myled4'.

and

http://<your_mbed_ip>/RPC/myled4/write 1 - - > to switch on the LED4.

Of course it is possible to Register your own objects with the standard MBED RPC functionality.

All the above Scenarios are implemented in a sample application, which will allow you to try out the functionality with basically no changes. If you want to try out the HTTP file Server, it is of course helpful to upload an html file to your MBED local storage.

Here is the sample application :

Import programEthHTTPServer

Working sample implementation for the EthernetInterface HTTPServer.

Last commit 17 Aug 2013 by Henry Leinen

Future plans

Currently I am not considering to further extend this library. However, if someone needs extensions to this library, I will consider implementing them. Of course I will be taking care of bugfixes.

Known issues

Please note that the current implementation of the EthernetInterface seems to have an issue which results in unresponsive behaviour of the Sockets in some situations. This odd behaviour has not only been reported on my HTTPServer but also on other components using the EthernetInterface library.

HTTPServer.cpp

Committer:
leihen
Date:
2013-08-17
Revision:
14:011edcd33e86
Parent:
13:aa5338a5e452
Child:
16:cc3f5c53d0d5

File content as of revision 14:011edcd33e86:

#include "mbed.h"
#include "HTTPServer.h"
#define DEBUG
#include "debug.h"

#define _DEBUG      1

#ifdef _DEBUG
DigitalOut led1(LED1);
DigitalOut led2(LED2);
DigitalOut led3(LED3);
DigitalOut led4(LED4);
#endif


/* Constructor */
/* initialize all members and set the standard error handler. */
HTTPServer::HTTPServer()
    : m_pEthernet(NULL)
{
    m_pErrorHandler = StdErrorHandler;
}

HTTPServer::~HTTPServer()
{
    if (m_pEthernet == NULL) {
        INFO("Deleting EthernetInterface Object.\n");
        delete m_pEthernet;
    }
}

static const char* szStdErrorPage = "<HTML><HEAD><META content=\"text/html\" http-equiv=Content-Type></HEAD><BODY><h1>Error 404</h1><P>This resource is not available<P></BODY></HTML>\r\n\r\n";

void HTTPServer::StdErrorHandler(HTTPConnection::HTTPMessage& msg, TCPSocketConnection& tcp)
{
    char echoHeader[256];
    tcp.set_blocking(true, 1500);
    sprintf(echoHeader,"HTTP/1.0 404 Fail\r\nConnection: close\r\nContent-Length: %d\r\nContent-Type: text/html\r\nServer: mbed embedded\r\n\n\r",strlen(szStdErrorPage));
    tcp.send(echoHeader, strlen(echoHeader));
    tcp.send((char*)szStdErrorPage, strlen(szStdErrorPage));
}


bool HTTPServer::start(int port, EthernetInterface* pEthernet)
{
    //  If no ethernet interface is provided, instantiate own on the heap. This has to be deleted later in the destructor.
    //  If a valid pointer to an thernet interface is proveded, we can simply use it. 
    if (pEthernet == NULL) {
        INFO("Creating EthernetInterface object\n");
        m_pEthernet = new EthernetInterface();
        
        if (m_pEthernet == NULL) {
            ERR("Out of memory, unable to instantiate an EthernetInterface object.");
            return false;
        }

        //  Initiaize the network
        INFO("Initializing network\n");
        if (m_pEthernet->init() != 0) {
            ERR("Failed to initialize the ethernet interface !");
            delete m_pEthernet;
            m_pEthernet = NULL;
            return false;
        }
        
        //  Connect to the network using DHCP
        INFO("Connecting to the network using DHCP...");
        if (m_pEthernet->connect() != 0) {
            ERR("Failed to connect to the ethernet !");
            delete m_pEthernet;
            m_pEthernet = NULL;
            return false;
        }
        
        INFO("Connected IP %s", m_pEthernet->getIPAddress());
        
    } else {
        //  In the case that the ethernet interface is provided, it is assumed that a connection has already been created.
        INFO("Using connection IP %s", pEthernet->getIPAddress());
    }
    
    INFO("Binding to port %d...", port);
    if (m_Svr.bind(port) < 0) {
        ERR("Failed to bind to port !\n");
        error("Binding");
        return false;
    }

    INFO("Listening ...");
    if (m_Svr.listen(1) < 0) {
        ERR("Failed to listen !\n");
        error("Listening");
        return false;
    }

    ERR("Connected !");
    //  set into non blocking operation
    m_Svr.set_blocking(false, 100);

    return true;
}


int HTTPServer::poll(bool blocking)
{
#ifdef _DEBUG
    led4 = 1;   //  Indicate we are waiting for a new connection
#endif
    //  This thread basically checks if there is a new incoming connection.
    //  If so , a new HTTPConnection is created and the connection thread is started.
    TCPSocketConnection Clnt;
    if (m_Svr.accept(Clnt) < 0) {
#ifdef _DEBUG
        led4 = 0;
        led3 = 1;   //  ERROR
        led2 = 0;
        led1 = 0;
#endif
        return -1;
    }

    //   a new connection was received
    INFO("Client (IP=%s) is connected !\n", Clnt.get_address());
#ifdef _DEBUG
    led4 = 0;
    led3 = 0;
    led2 = 0;
#endif

#ifdef _DEBUG
    led3 = 1;
    led2 = 1;
#endif
    HTTPConnection con(Clnt);
    int c = con.poll();
    if (c == 0) {
        //  Handle the request
        INFO("Handling request !");
        HandleRequest(con.m_Msg, Clnt);
    }
    if (c == -1) {
//        break;
    }
#ifdef _DEBUG
    led2 = 0;
    led3 = 0;
#endif


    INFO("Leaving polling thread");
    return 0;
}

void HTTPServer::HandleRequest(HTTPConnection::HTTPMessage& msg, TCPSocketConnection& tcp)
{
    std::string localPath;
    std::map<std::string, HTTPRequestHandler*(*)(const char*, const char*, HTTPConnection::HTTPMessage&, TCPSocketConnection&), handlersComp>::const_iterator it;

    //  Iterate through registered handlers and check if the handler's path is a subset of the requested uri.
    for (it = m_lpHandlers.begin() ; it != m_lpHandlers.end() ; it++) {
        //  check if this entries' path is fully contained at the beginning of the requested path
        std::string curpth = it->first;

        if (msg.uri.find(curpth) == 0) {
            // firts matching handler found, we just take it and we'll be happy
            localPath = msg.uri.substr(curpth.length());
            break;
        }
    }

    if (it == m_lpHandlers.end()) {
        //  There is no such handler, so return invalid

        m_pErrorHandler(msg, tcp);
        INFO("Webrequest left unhandled.");
    } else {
        //  Valid handler was found
        INFO("Routing webrequest !");
        //  Instantiate the handler object (handling will be done from withing the object's constructor
        HTTPRequestHandler *phdl = (*it->second)(it->first.c_str(), localPath.c_str(), msg, tcp);
        //  now we can delete the object, because handling is completed.
        if (phdl != NULL)
            delete phdl;
    }
}