What's the maximum length of an HTTP GET request? Is there a response error defined that the server can/should return if it receives a GET request exceeds this length?
update: as indicated in the tags, this is in the context of a web service API, although it's interesting to see the browser limits as well.
Similar question here: http://stackoverflow.com/questions/266322/http-uri-get-limit
I've hit the limit and on my shared hosting account but the browser returned a blank page before it got to the server I think.
There's no defined limit. However, most browsers have limit of about 2048 characters.
The limit is dependent on both the server and the client used (and if applicable, also the proxy the server or the client is using).
Most webservers have a limit of 8192 bytes (8KB), which is usually configureable somewhere in the server configuration. As to the client side matter, the HTTP 1.1 specification even warns about this, here's an extract of chapter 3.2.1:
Note: Servers ought to be cautious about depending on URI lengths above 255 bytes, because some older client or proxy implementations might not properly support these lengths.
The limit is in MSIE and Safari about 2KB, in Opera about 4KB and in Firefox about 8KB. We may thus assume that 8KB is the maximum possible length and that 2KB is a more affordable length to rely on at the server side and that 255 bytes is the safest length to assume that the entire URL will come in.
If the limit is exceeded in either the browser or the server, most will just truncate the characters outside the limit without any warning. Some servers however may send a HTTP 414 error. If you need to send large data, then better use POST instead of GET. Its limit is much higher, but more dependent on the server used than the client. Usually up to around 2GB is allowed by the average webserver. This is also configureable somewhere in the server settings. The average server will display a server-specific error/exception when the POST limit is exceeded, usually as HTTP 500 error.
You are asking two separate questions here:
What's the maximum length of an HTTP GET request?
As already mentioned, HTTP itself doesn't impose any hard-coded limit on request length; but browsers have limits ranging on the 2kb - 8kb (255 bytes if we count very old browsers).
Is there a response error defined that the server can/should return if it receives a GET request exceeds this length?
That's the one nobody has answered.
HTTP 1.1 defines Status Code 414 Request-URI Too Long for the cases where a server-defined limit is reached. You can see further details on W3C's RFC 2616.
For the case if client-imposed limits, there is no sense on the server returning something, because the client won't sent the request at all.
Hope this helps.