New Logbook and Spotter on Copasetic Flows

There's are two new applications at copaseticflows. The front page now geographically displays the most recent calls from both dxsummit.fi and the copaseticflows logbook. That brings us to the second new application, the copaseticflows logbook. You can log, store, search, and map your calls for free. The new front page can be seen at:

copaseticflows.appspot.com

and the new logbook application can be used at:

copaseticflows.appspot.com/cflogbook

Have fun!

Gadget Google Math Formula Tester

The Google Chart Formula API Tester is now available as a gadget!

You can install this gadget on your own iGoogle home page, or on any web page by using the installer from Google.

Google Mathematical Formula API Tester

Google has come out with a handy URL based API for adding mathematical formulas to html documents. I haven't seen a GUI tester for this yet, so I'm adding one here.

All formula image links start with the address

http://chart.apis.google.com/chart?cht=tx&chl=

The code that follows the link describes the formula to be displayed. For example, the tester on this page loads with the quadratic formula. Documentation on the TeX codes used to create formulas can be found on Wikipedia at:

http://en.wikipedia.org/wiki/Help:Displaying_a_formula

To use the tester, place your formula tags in the text field labeled 'Formula'. Then click, 'Test Formula' to see the formula as it will be displayed. The 'Formula URL' box will contain your formula encoded into the proper web address.

Formula
Formula URL

App Engine and long Post URLs Error 414

I've been working on an applciation utilizing Google's App Engine. The fist version of my application sent about 500 bytes of information along with each user POST request. The second version up this to around 100 bytes and the App Engine server started giving the error:

Requested URI too long: ... HTTP/1.1" 414 –

This is the http error returned when a post request is longer than the server is configured to accept. After a little research I found this excellent article:

http://www.openjs.com/articles/ajax_xmlhttp_using_post.php

that solved my problem. The short version of the article is:

Don’t send the post parameters as part of the url, send them using the XMLHTTP object’s send method once the object has been opened using only the address, (everything before the ?), of the original post url.

So, the original code that looked like:

var my_url = "/myhandler?longstring=" +

encodeURIComponent(longstring) +

//Now send the string to the db

if (typeof XMLHttpRequest != "undefined") {

req = new XMLHttpRequest();

} else if (window.ActiveXObject) {

req = new ActiveXObject("Microsoft.XMLHTTP");

}

req.open("POST", my_url, true);

req.onreadystatechange = my_cb;

req.send(null);

Becomes code that looks like:

var my_url = "longstring=" +

encodeURIComponent(longstring) +

//Now send the string to the db

if (typeof XMLHttpRequest != "undefined") {

req = new XMLHttpRequest();

} else if (window.ActiveXObject) {

req = new ActiveXObject("Microsoft.XMLHTTP");

}

req.open("POST", '/myhandler', true);

req.setRequestHeader("Content-type",

"application/x-www-form-urlencoded");

req.setRequestHeader("Content-length", score_params.length);

req.setRequestHeader("Connection", "close");

req.onreadystatechange = log_scores_cb;

req.send(score_params);

Notice that the call to send was changed from a null argument to the POST command arguments sent in the original URL. Also notice that the length of the parameters was sent to the server ahead of time in the 'Content-length' header.