bgpmap/?q={"....."} strings can get too long for GET

[tbaschak]

I've noticed occasional broken images on some bgpmaps from the NLNOG RING LG, and upon deeper investigation some prefixes which contain longer AS-PATHs (usually those with multiple prepends) which are visible via significant chunks of the internet generate a very long bgpmap/?q={"....."} URL to the image generation script. I've seen some over 9500 characters.

An example of such a prefix. If you click the broken image link you'll likely get a HTTP 414 "Request URI too long" error.

Potential workaround to the problem:
Clicking the link to view the image full size could be a form submission and use POST, however I don't know how you'd go about solving that for the thumbnail that is currently linked to the full size image.

[mweinelt]

Can be worked around also in the webserver:

• Apache: http://httpd.apache.org/docs/2.2/mod/core.html#limitrequestline
• nginx: http://nginx.org/en/docs/http/ngx_http_core_module.html#large_client_header_buffers

[tbaschak]

Had @job test this workaround on the webserver side of the NLNOG Ring LG and it seems to be working.
With a documentation update/note, this could likely resolve the problem for many people and would require no code effort.