HTTP Server
This page explains how to implement an HTTP Server on your mbed. It uses the Networking stack.
Hello World!¶
#include "mbed.h"
#include "EthernetNetIf.h"
#include "HTTPServer.h"
EthernetNetIf eth;
HTTPServer svr;
DigitalOut led1(LED1);
int main() {
printf("Setting up...\n");
EthernetErr ethErr = eth.setup();
if(ethErr)
{
printf("Error %d in setup.\n", ethErr);
return -1;
}
printf("Setup OK\n");
svr.addHandler<SimpleHandler>("/"); //Default handler
svr.bind(80);
printf("Listening...\n");
Timer tm;
tm.start();
//Listen indefinitely
while(true)
{
Net::poll();
if(tm.read()>.5)
{
led1=!led1; //Show that we are alive
tm.start();
}
}
return 0;
}
This program is available here:
» Import this programHTTPServerHelloWorld
Last commit 09 Jul 2010 by 
Donatien Garnier
Packages¶
Precompiled version:
» Import this library into a programHTTPServer
This library is deprecated.
Last commit 05 Aug 2010 by Donatien Garnier
Library¶
Architecture¶
The HTTPServer is composed of:
- The actual server (HTTPServer)
- A request dispatcher, instanciated on each request (HTTPRequestDispatcher)
- Request handlers instanciated by the dispatcher(deriving from HTTPRequestHandler)
HTTP Server Requests Handlers¶
- Simple "Hello world" handler
- Filesystem handler
- RPC handler
You can also Create your custom handler.
Includes¶
#include "HTTPServer.h"
Reference¶
» Import this program
Public Member Functions |
|
| HTTPServer () | |
|
Instantiates the HTTP Server.
|
|
| template<typename T > | |
| void | addHandler (const char *path) |
|
Adds a handler.
|
|
| void | bind (int port=80) |
|
Starts listening.
|
|
Bind the server to port port and start listening. This function returns immediately. You must call Net::poll() regularly after this so that the server serves requests properly.
Examples¶
This example sets the server up and demonstrates the use of all-three kinds of handlers.
The local file system is available either under the /files/ path. Since FSHandler is the default handler here, the mbed file system (/webfs/) is made available on the root path of the server as well, so mbed.htm is available at the URLs http://a.b.c.d/files/mbed.htm and http://a.b.c.d/mbed.htm, where a.b.c.d is your mbed's IP address.
#include "mbed.h"
#include "EthernetNetIf.h"
#include "HTTPServer.h"
DigitalOut led1(LED1, "led1");
DigitalOut led2(LED2, "led2");
DigitalOut led3(LED3, "led3");
DigitalOut led4(LED4, "led4");
LocalFileSystem fs("webfs");
EthernetNetIf eth;
HTTPServer svr;
int main() {
Base::add_rpc_class<DigitalOut>();
printf("Setting up...\n");
EthernetErr ethErr = eth.setup();
if(ethErr)
{
printf("Error %d in setup.\n", ethErr);
return -1;
}
printf("Setup OK\n");
FSHandler::mount("/webfs", "/files"); //Mount /webfs path on /files web path
FSHandler::mount("/webfs", "/"); //Mount /webfs path on web root path
svr.addHandler<SimpleHandler>("/hello");
svr.addHandler<RPCHandler>("/rpc");
svr.addHandler<FSHandler>("/files");
svr.addHandler<FSHandler>("/"); //Default handler
//Example : Access to mbed.htm : http://a.b.c.d/mbed.htm or http://a.b.c.d/files/mbed.htm
svr.bind(80);
printf("Listening...\n");
Timer tm;
tm.start();
//Listen indefinitely
while(true)
{
Net::poll();
if(tm.read()>.5)
{
led1=!led1; //Show that we are alive
tm.start();
}
}
return 0;
}
You can also directly import this example there:
» Import this programHTTPServerExample
Last commit 09 Jul 2010 by Donatien Garnier
Robustness¶
Although this HTTP Server should still be considered in beta phasis, it has been built for robustness. A good test is this web page that you can use with the previous example: put it on your mbed and open it in your browser (at an address like http://a.b.c.d/webfs/stress.htm): http://mbed.org/media/uploads/donatien/stress.htm.
It will start an asynchronous HTTP Request every 100ms, sending RPC commands to set the leds on and off. You will see that all requests are not successfully processed, but the server will not crash and will remain up and running properly after you close the page.
License¶
Post a comment Donatien Garnier.
43 comments
43 comments:
C Neroth wrote:
Does every LPC1768 board have a built in ip address? Or is this assignable? Where is this already explained? I am very new to this product and this forum...
By default, the server will request an IP address using DHCP. You can see the address it has been allocated on the console output. Of course this only works if your network has a DHCP server.
Alternatively you can specify a static IP address when you instantiate the server.
Dario Delvalle wrote:
Hi all
What does net::poll() function do?. Which is the library to it belongs?. I found no information about it.
Hi Dario, This question has been asked a few times so I thought that I'd actually put an answer in: - The NetServices library is polled. To execute the polling action, the net::poll() is called - preferably very often (ie every iteration of the execution loop in main() ) If there is data on the Ethernet (and thus in the TCP/IP stack) that data will be processed when this is called.
This includes parsing the inbound data, determining if there is a handler for the request and then executing that handler. As an example, if an HTTP handler is defined and a request comes in, it then locates an appropriate HTTP_Handler and returns a response.
The source code for this call can be found in the NetServices library: /core in the net.h and net.cpp files.
Regards,
Anthony
Hirofumi Inomata wrote:
Hi, I would like to make a new RequestHander as your SimpleHandler. So, I need a sample source code of SimpleHander.cpp, because I can't understand more description by articles in this site.
I had found it in the url, http://mbed.org/users/segundo/libraries/NetServices/ljhqix/docs/SimpleHandler_8cpp_source.html
Dario Delvalle wrote:
file system handler (FShandler)serves only html files?. how it works exactly? Regards
it serves any files. If you want web browser no display the file (image, text, etc) you have to add in the header response the field "content-disposition".
s.j.saunders@... wrote:
Do you have an example for the RPC DigitalOut so I can create additional functions like PwmOut and DigitalIn?
take a look at this http://mbed.org/cookbook/RPC-Interface-Library.
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