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:
2013-06-01
Revision:
6:fe661fa9d18a
Parent:
5:dc88012caef1
Child:
9:c2a1462b9b71

File content as of revision 6:fe661fa9d18a:

#include "mbed.h"
#include "HTTPServer.h"

#define _DEBUG      0

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

#if (_DEBUG && !defined(TARGET_LPC11U24))
#define INFO(x, ...) if (m_pDbg) m_pDbg->printf("[HttpServer : DBG]"x"\r\n", ##__VA_ARGS__); else printf("[HttpServer : DBG]"x"\r\n", ##__VA_ARGS__);
#define WARN(x, ...) if (m_pDbg) m_pDbg->printf("[HttpServer : WARN]"x"\r\n", ##__VA_ARGS__); else printf("[HttpServer : DBG]"x"\r\n", ##__VA_ARGS__);
#define ERR(x, ...) if (m_pDbg) m_pDbg->printf("[HttpServer : ERR]"x"\r\n", ##__VA_ARGS__); else printf("[HttpServer : DBG]"x"\r\n", ##__VA_ARGS__);
#else
#define INFO(x, ...)
#define WARN(x, ...)
#define ERR(x, ...)
#endif


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

HTTPServer::~HTTPServer()
{
    if (m_pSvr) {
        delete m_pSvr;
        m_pSvr = NULL;
    }
}


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/1.1 404 Fail\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));
}


int HTTPServer::start(int port)
{
    // check if the start member was called already once
    if (m_pSvr != NULL) {
        ERR("start function was already called, server is already in listening state.");
        return -1;
    }
    
    //  Create a new server object
    m_pSvr = new TCPSocketServer();
    
    //  Bind the local server to the given port
    if (m_pSvr->bind(port) < 0) {
        ERR("Failed to bind to port %d\n", port);
        return -1;
    }
    else {
        INFO("Binding succeeded !\n");
    }

    //  Listen to a maximum of 10 concurrent connections
    if (m_pSvr->listen(1) < 0) {
        ERR("Faild to listen !\n");
        delete m_pSvr;
        m_pSvr = NULL;
        return -1;
    }
    else {
        INFO("Listening\n");
    }

    //  set into non blocking operation
    m_pSvr->set_blocking(false, 100);
    
    return 0;
}


int HTTPServer::poll(bool blocking)
{    
    int retval = -1;
    INFO("Listening for new connection requests.");

    //  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;

#ifdef _DEBUG
    led4 = 1;   //  Indicate we are waiting for a new connection 
#endif
    m_pSvr->set_blocking(blocking); 
    retval = m_pSvr->accept(Clnt);
    if (retval > 0) {
        // no connection availale yet, so just return
#ifdef _DEBUG
led4 = 0;
led3 = 0;
led2 = 0;
#endif
        return retval;
    }
    if ( retval < 0) {
        //  an error occured 
        ERR("There was an error, Accept returned with an error. Probably the connection to the router was lost. Shutting down server");
#ifdef _DEBUG
        led2 = 0;
#endif 
        m_pSvr->close();
        delete m_pSvr;
        m_pSvr = NULL;
#ifdef _DEBUG
        led4 = 0;
        led3 = 1;   //  ERROR
        led2 = 0;
        led1 = 0;
#endif
        return -1;
    }
    else {
#ifdef _DEBUG
        led4 = 0;
#endif 
        //   a new connection was received
        INFO("Client (IP=%s) is connected !\n", Clnt.get_address());
        //  Start the main connection thread
#ifdef _DEBUG
        led3 = 1;
        led2 = 1;
#endif
        HTTPConnection con;
        int c = con.poll();
        if (c == 0) {
            //  Handle the request
            HandleRequest(con.m_Msg, Clnt);
        }
#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;
    }
}