Clearly I need a REST

Jeff Lockyear

As an Accidental Programmer I sometimes run across a problem that requires knowledge, rather than brute force, and I think this is one of those times.

I have one of the little Roku media streamers, which has external control support (found here):

http://sdkdocs.roku.com/display/sdkdoc/External+Control+Guide

I can establish a connection with my master on the correct port, but I just can't get my commands acted upon. I've tried various iterations of what's in the examples, but it seems (for example) a Home button emulation should be sent as (after a successful connection) POST /keypress/Home

At least I think so. If anyone can offer an educated opinion as to how the string needs to actually be formatted I'd appreciate it. All the online help examples involve various.cryptic.libraries that I don't have the depth to understand.

ericmedley

Jeff,
Can you post the code with your string build too? Might help.
E

Jeff Lockyear

Sure! Through the course of testing and head beating I've ended up reducing it to the super simple:

DEFINE_DEVICE 

    dvRoku	= 0:3:0
    vdvRoku = 33001:1:0

DEFINE_EVENT

DATA_EVENT [dvRoku]
{
    ONLINE: SEND_STRING dvRoku, 'POST /keypress/Home'  // 'POST /keypress/Home HTTP/1.1' 
}

CHANNEL_EVENT [vdvRoku,1]
{
    ON: IP_CLIENT_OPEN (dvRoku.Port,'192.168.1.20',8060,1)
}	

Thanks! I have the Roku up on the TV and I'm not on the Home screen, so I would know if this command worked.

nickm

Here's a snippet of how an HTTP header should be formed. This particular example is from my BoxeeBox control module which uses the same RESTful scheme (though different commands)

DEFINE_FUNCTION AddHTTPGet(CHAR cShortURI[]) {
	//---Add an HTTP GET request to BBox.Comm.cQue
	//---To be instantiated by SendQue above
	
	STACK_VAR CHAR cURLString[512]
	STACK_VAR CHAR cHeader[512]
	
	cURLString = "'/',cShortURI"
	DebugString(4,"'Add to Que: HTTP://',BBox.Comm.cIPAddress,cURLString")
	
	cHeader = "'GET ',cURLString,' HTTP/1.1',$0D,$0A"
	cHeader = "cHeader,'Host: ',BBox.Comm.cIPAddress,$0D,$0A"
	cHeader = "cHeader,'User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64,rv:13.0) Gecko/20100101 Firefox/13.0.1',$0D,$0A"
	cHeader = "cHeader,'Accept: text/html,application/xhtml+xml,application/xml;q=0.9*/*;q=0.8',$0D,$0A"
	cHeader = "cHeader,'Accept-Language: en-us;q=0.5',$0D,$0A"
	cHeader = "cHeader,'Accept-Encoding: gzip,deflate',$0D,$0A"
	cHeader = "cHeader,'Connection: keep-alive',$0D,$0A,$0D,$0A"
	
	BBox.Comm.cQue = "BBox.Comm.cQue,cHeader,$0B,$0B"
	DebugString(3,"'AddHTTPGet : ',cShortURI")
}

You can find the entire module here: https://github.com/nickmil/BoxeeBox

As you can see, there is a lot of information required of an HTTP header. A tool that will come in quite handy as you play more with RESTful APIs is the POSTman REST client. It's a Chrome app that breaks down everything that happens in a REST request and response.

Jeff Lockyear

Yup, that looks quite different to what I have.

nickm

The equivalent here would be your '/keypress/home' string.

Jeff Lockyear

nickm,

I replaced your GET with POST in the function and gave it a try with my Home command and it worked, thanks. I guess the Roku document assumes a level of http/REST knowledge that I don't have.

Cheers!

PhreaK

If you want a quick and painless intro to REST there's a great 15 minute talk on the Google Developers channel.

Jeff Lockyear

Ah, cool, I'll check that out. Thanks!

DHawthorne

You don't necessarily need all that header information ... especially the "CONNECTION: keep_alive field." In fact, that one might even be hurting you by forcing the connection to stay open after it's finished. I was stunned how much more responsive a weather module worked when I replaced that with "CONNECTION: close." What I do on all my HTTP mods is to start with a full-blown header, then take stuff out one at a time until it breaks. Then I know I have it reduced to what is really needed to make it work.

nickm

DHawthorne wrote: »

You don't necessarily need all that header information ...

Agreed. There is a lot of header information that typically isn't needed in the scope of devices/services we are communicating with.

vining

Here's an example of what I would observe in WireShark between my PC and a particular device:

SEND_STRING dvJSON,"'POST /jsonrpc.js HTTP/1.1',STR_CRLF"; 
		    SEND_STRING dvJSON,"'Host: ',sJSON.sPlayer.cIP,':',itoa(sJSON.sPlayer.nPort),STR_CRLF";
		    SEND_STRING dvJSON,"'User-Agent: Netlinx',STR_CRLF";
		    //SEND_STRING dvJSON,"'User-Agent: User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:27.0) Gecko/20100101 Firefox/27.0',STR_CRLF";
		    SEND_STRING dvJSON,"'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',STR_CRLF"; 
		    SEND_STRING dvJSON,"'Accept-Language: en-us',STR_CRLF";
		    SEND_STRING dvJSON,"'Accept-Encoding: gzip, deflate',STR_CRLF";
		    SEND_STRING dvJSON,"'X-Requested-With: XMLHttpRequest',STR_CRLF";
		    SEND_STRING dvJSON,"'Content-Type: application/x-www-form-urlencoded; charset=UTF-8',STR_CRLF";
		    SEND_STRING dvJSON,"'Referer: http://',sJSON.sPlayer.cIP,':',itoa(sJSON.sPlayer.nPort),'/',STR_CRLF";
		    SEND_STRING dvJSON,"'Content-Length: ',itoa(length_string(sJSON.sPlayer.cFullCmd)),STR_CRLF";
		    SEND_STRING dvJSON,"'Cookie: Squeezebox-player=',fnEncodeURL(sJSON.sPlayer.cStrMAC),'; Squeezebox-expandPlayerControl=false; ',
		    'Squeezebox-expanded-MY_MUSIC=1; Squeezebox-expanded-RADIO=0; Squeezebox-expanded-PLUGIN_MY_APPS_MODULE_NAME=1; ',
		    'Squeezebox-expanded-FAVORITES=0; Squeezebox-expanded-PLUGINS=0; Squeezebox-playersettings=null; ',
		    'Squeezebox-advancedsettings=settings/server/debugging.html%3F; Squeezebox-expanded-updatePlugins=1; ',
		    'Squeezebox-expanded-activePlugins=1; Squeezebox-expanded-inactivePlugins=1; Squeezebox-expanded-otherPlugins0=1; ',
		    'Squeezebox-expanded-otherPlugins1=1; __utma=124789194.27251913.1391382619.1391382619.1391382619.1; ',
		    '__utmz=124789194.1391382619.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)',STR_CRLF";
		    SEND_STRING dvJSON,"'Connection: keep-alive',STR_CRLF";
		    SEND_STRING dvJSON,"'Pragma: no-cache',STR_CRLF";
		    SEND_STRING dvJSON,"'Cache-Control: no-cache',STR_CRLF";
		    SEND_STRING dvJSON,"STR_CRLF";
		    SEND_STRING dvJSON,"sJSON.sPlayer.cFullCmd,STR_CRLF";

and then as Dave mentioned I would get it working using everything that I observed being used and then comment out a line or more at a time and test. In the end all I ended up needing was:

SEND_STRING dvJSON,"'POST /jsonrpc.js HTTP/1.1',STR_CRLF"; 
		    SEND_STRING dvJSON,"'Host: ',sJSON.sPlayer.cIP,':',itoa(sJSON.sPlayer.nPort),STR_CRLF";
		    SEND_STRING dvJSON,"'Referer: http://',sJSON.sPlayer.cIP,':',itoa(sJSON.sPlayer.nPort),'/',STR_CRLF";
		    SEND_STRING dvJSON,"'Content-Length: ',itoa(length_string(sJSON.sPlayer.cFullCmd)),STR_CRLF";
		    SEND_STRING dvJSON,"STR_CRLF";
		    SEND_STRING dvJSON,"sJSON.sPlayer.cFullCmd,STR_CRLF";