bad request with UrlFetchApp - google-apps-script

Question

Looking for some help connecting to this service and returning the xml.
Here are the instructions (from here):
The state of the inputs and relays can be monitored by sending a
request to port 80 (or port specified in setup) for the XML page
state.xml. The relays can be controlled by sending GET requests to the
same page on port 80 (or port specified in setup). This can be
demonstrated by entering commands into the URL line of a web browser.
Request the current state: http://"ip address"/state.xml
...
If the control password is enabled in the WebRelay-DualTM unit and
the state.xml page is requested through a browser, the browser will
prompt the user for the password. If the XML request is sent from
another application and not a browser, the html request will need to
contain the password encoded using the base 64 encoding scheme. The
html request header without the password looks like this:
GET /state.xml?relay1State=1&noReply=1 HTTP/1.1 (Ends with two \r\n)
The html request header with the password looks like this:
GET /state.xml?relay1State=1&noReply=1 HTTP/1.1(\r\n here)
Authorization: Basic bm9uZTp3ZWJyZWxheQ== (Ends with two \r\n)
where bm9uZTp3ZWJyZWxheQ== is the base 64 encoded version of the
user name and password none:webrelay
Code:
function webRelay(){
//working url http://75.65.130.27/state.xml
var url = 'http://75.65.130.27/';
var params = encodeURIComponent('state.xml');
Logger.log(params);
var headers = {
"Authorization" : "Basic" + Utilities.base64Encode('none:webrelay')
};
var options =
{
"method" : "get",
"headers" : headers
};
var state = UrlFetchApp.fetch(url+params, options);
Logger.log('1: '+state);
Logger.log(parse(state));
}
function parse(txt) {
var doc = Xml.parse(txt, true);
}
Any help is much appreciated.

Answer 1

There are a couple of coding errors that you can easily take care of:
In the Authorization header you need a space after "Basic".
Authorization : "Basic " + Utilities.base64Encode(username+':'+password)
urlFetchApp.fetch() returns an HTTP Response object, so you need to extract the contents for parsing.
var result = UrlFetchApp.fetch(url, options);
var state = result.getContentText();
You aren't returning anything from your parse() function.
You should check result.getResponseCode() after .fetch(), and handle errors before proceeding with parsing.
That said, I keep getting Bad request: http://75.65.130.27/state.xml errors, so something is still not right. This is an HTTP 400 response, and google's servers don't return anything to the script debugger to dig into it. You should check the username & password, although I'd expect a 401-Unauthorized response if they were wrong. I tried including a payload of relay1State=2, and got the same Bad request result. If you can capture the HTTP Request hitting your server, there may be a clue to what is malformed. This could also be the result of a firewall.
Once that's sorted, this tutorial should help with the XML Parsing.
Here's my edit of your code:
function webRelay(){
var url = 'http://75.65.130.27/state.xml';
var username = "none";
var password = "webrelay";
var headers =
{
Authorization : "Basic " + Utilities.base64Encode(username+':'+password)
}
var options =
{
"method" : "get",
"headers": headers
};
// Getting "bad request" here - check the username & password
var result = UrlFetchApp.fetch(url, options);
var state=result.getContentText();
// You should check state.getResponseCode()
Logger.log('1: '+state);
Logger.log(parse(state));
}
function parse(txt) {
var doc = Xml.parse(txt, true);
return doc; // Return results
}