Simple Embedded Server Pages (ESP) Sample in C

The simple HTTP server sample demonstrates how to use Embedded Server Pages within your application to create dynamically generated web pages. This sample adds HTTP server functionality and ESP support to a main program.

The sample is a multithreaded main program that listens on port 8888 for HTTP requests. By changing the value of the ThreadLimit directive in the configuration file to zero you can run single-threaded.

See also the equivalent C++ simpleEsp sample.

Files

index.esp
simpleEsp.conf
Makefile
simpleEsp.c

index.esp Web Page

<HTML>
<HEAD>
<TITLE>Simple ESP Test Page</TITLE>
</HEAD>

<BODY>

<p>Calling the ESP procedure <b>helloWorld</b></p>

<% result = helloWorld("1", 2, 3, 4, "5"); %>
<p>Result is: @@result</p>

<h2>Some Test ESP calls</h2>

<% i=2;%>
<% write("i is " + i);%>

<% write("REMOTE_ADDR: " + REMOTE_ADDR);%> <br/>
<% write("QUERY_STRING: " + QUERY_STRING);%> <Br/>
<% write("AUTH_TYPE: " + AUTH_TYPE);%> <Br/>
<% write("CONTENT_LENGTH: " + CONTENT_LENGTH);%> <Br/>
<% write("CONTENT_TYPE: " + CONTENT_TYPE);%> <Br/>
<% write("GATEWAY_INTERFACE: " + GATEWAY_INTERFACE);%> <Br/>
<% write("PATH_INFO: " + PATH_INFO);%> <br/>
<% write("PATH_TRANSLATED: " + PATH_TRANSLATED);%> <br/>
<% write("QUERY_STRING: " + QUERY_STRING);%> <br/>
<% write("REMOTE_ADDR: " + REMOTE_ADDR);%> <br/>
<% write("REMOTE_USER: " + REMOTE_USER);%> <br/>
<% write("REQUEST_METHOD: " + REQUEST_METHOD);%> <br/>
<% write("SERVER_NAME: " + SERVER_NAME);%> <br/>
<% write("SERVER_PORT: " + SERVER_PORT);%> <br/>
<% write("SERVER_PROTOCOL: " + SERVER_PROTOCOL);%> <br/>
<% write("SERVER_SOFTWARE: " + SERVER_SOFTWARE);%> <br/>
<% write("HTTP_HOST: " + HTTP_HOST);%> <br/>
<% write("HTTP_USER_AGENT: " + HTTP_USER_AGENT);%> <br/>
<% write("HTTP_CONNECTION: " + HTTP_CONNECTION);%> <br/>

<% for (i = 0;i < 3; i++) {
write("<p>Line " + i + "</p>");
}
%>

</BODY>
</HTML>

Configuration File

simpleEsp.conf

DocumentRoot "."
Listen 8888
ThreadLimit 4
AddHandler espHandler .esp
AddHandler copyHandler

The simpleEsp.conf file is an AppWeb configuration file. It is configured to run single-threaded and assumes that the sample is being run from the current directory.

You should modify the DocumentRoot and Listen directives to suit your application's needs.

Makefile

The Makefile will build on Windows or Linux. A Windows VS 6.0 project file is also supplied.

Typical output from the Makefile build is listed below. This is the output on a Windows system:

cl -o simpleEsp.exe simpleEsp.c -Zi -Od -D_NDEBUG -W3 -nologo -MDd -FD -DWIN -D_DLL -D_MT \
  -D_WINDOWS -DWIN32 -D_WIN32_WINNT=0x500 -D_X86_=1 -D_CRT_SECURE_NO_DEPRECATE -D_USRDLL \
  -I../../../include  ../../../bin/libappWebStatic.lib ws2_32.lib advapi32.lib user32.lib

Source Code

simpleEsp.c

/*
 *  @file   simpleEsp.c
 *  @brief  Demonstrate the use of Embedded Server Pages (ESP) in a 
 *          simple multi-threaded application.
 *  Copyright (c) Mbedthis Software LLC, 2003-2005. All Rights Reserved.
 */
/******************************* Includes *****************************/

#define     UNSAFE_FUNCTIONS_OK 1

#include    "appWeb/appWeb.h"

/********************************* Code *******************************/
#if BLD_FEATURE_C_API_MODULE

/*
 *  Function that is run when the ESP procedure is called from the web
 *  page. Rq is the request context. Argv is the parameters to the
 *  ESP procedure defined in the web page.
 */

static int myEsp(EspRequest *ep, int argc, char **argv)
{
    char    *s;
    int     i;

    /*
     *  There are a suite of write calls available. This just writes a
     *  string.
     */
    espWriteString(ep, "<h1>Hello World</h1><p>Args: ");

    mprAssert(argv);
    for (i = 0; i < argc; ) {
        s = argv[i];
        espWriteString(ep, s);
        if (++i < argc) {
            espWriteString(ep, " ");
        }
    }
    espWriteString(ep, "</p>");

    /*
     *  Procedures can return a result
     */
    espSetReturnString(ep, "sunny day");
    return 0;
}

/**********************************************************************/

int main(int argc, char** argv)
{
    MaHttp      *http;      /* For the http service inside our app */
    MaServer    *server;    /* For a HTTP server */

    /*
     *  Initialize the run-time and give our app a name "simpleEsp"
     */
    mprCreateMpr("simpleEsp");

    /*
     *  Do the following two statements only if you want debug trace
     */
    mprAddLogFileListener();
    mprSetLogSpec("stdout:4");

    /*
     *  Start run-time services
     */
    mprStartMpr(0);

    /*
     *  Create the HTTP and server objects. Give the server a name 
     *  "default" and define "." as the default serverRoot, ie. the 
     *  directory with the server configuration files.
     */
    http = maCreateHttp();
    server = maCreateServer(http, "default", ".");
    
    /*
     *  Activate the handlers. Only needed when linking statically.
     */
    mprEspInit(0);
    mprCopyInit(0);

    /*
     *  Configure the server based on the directives in 
     *  simpleEsp.conf.
     */
    if (maConfigureServer(server, "simpleEsp.conf") < 0) {
        fprintf(stderr, 
            "Can't configure the server. Error on line %d\n", 
            maGetConfigErrorLine(server));
        exit(2);
    }

    /*
     *  Define our ESP procedures
     */
    espDefineStringCFunction(0, "helloWorld", myEsp, 0);
    
    /*
     *  Start serving pages. After this we are live.
     */
    if (maStartServers(http) < 0) {
        fprintf(stderr, "Can't start the server\n");
        exit(2);
    }

    /*
     *  Service events. This call will block until the server is exited
     *  Call mprTerminate() at any time to instruct the server to exit.
     *  The -1 is a timeout on the block. Useful if you use 
     *  MPR_LOOP_ONCE and have a polling event loop.
     */
    mprServiceEvents(MPR_LOOP_FOREVER, -1);

    /*
     *  Stop all HTTP services
     */
    maStopServers(http);

    /*
     *  Delete the server and http objects
     */
    maDeleteServer(server);
    maDeleteHttp(http);

    /*
     *  Stop and delete the run-time services
     */
    mprStopMpr();
    mprDeleteMpr();

    return 0;
}

/**********************************************************************/
#else /* BLD_FEATURE_C_API_MODULE */

int main()
{
    fprintf(stderr, "BLD_FEATURE_C_API_MODULE is not defined in config.h\n");
    exit(2);
}
#endif /* BLD_FEATURE_C_API_MODULE */

© Mbedthis Software LLC, 2003-2005. All rights reserved. Mbedthis is a trademark of Mbedthis Software LLC.