[Import] maximum URL length limit

Maximum URL length limit:

1. The URL cannot be greater than 255bytes, which is mentioned in RFC2616:
   

   The HTTP protocol does not place any a priori limit on the length of a URI. servers MUST be able to handle the URI of any resource they serve, and shocould be able to handle URIs of unbounded length if they provide GET-based forms that cocould generate such URIs. A server shoshould return 414 (Request-URI Too Long) status if a URI is longer than the server can handle (see section 10.4.15 ).

   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.

2. From the above, we can see that the 255bytes statement is also for compatibility consideration. In fact, modern browsers have the following restrictions:
   

   Microsoft Internet Explorer (browser)
   Microsoft states that the maximum length of a URL in Internet Explorer is 2,083 characters, with no more than 2,048 characters in the path portion of the URL. in my tests, attempts to use URLs longer than this produced a clear error message in Internet Explorer.
   Firefox (browser)
   After 65,536 characters, the location bar no longer displays the URL in Windows Firefox 1.5.x. However, longer URLs will work. I stopped testing after 100,000 characters.
   Safari (browser)
   At least 80,000 characters will work. I stopped testing after 80,000 characters.
   Opera (browser)
   At least 190,000 characters will work. I stopped testing after 190,000 characters. Opera 9 for Windows continued to display a fully editable, copyable and pasteable URL in the location bar even at 190,000 characters.
   Apache (server)
   My early attempts to measure the maximum URL length in web browsers bumped into a server URL length limit of approximately 4,000 characters, after which Apache produces a "413 Entity Too Large" error. I used the current up to date Apache build found in Red Hat Enterprise Linux 4. the official Apache documentation only mentions an 8,192-byte limit on an individual field in a request.
   Microsoft Internet Information Server
   The default limit is 16,384 characters (yes, Microsoft's web server accepts longer URLs than Microsoft's web browser). This is retriable.
   Perl http: daemon (server)
   Up to 8,000 bytes will work. those constructing web application servers with Perl's http: daemon module will encounter a 16,384 byte limit on the combined size of all HTTP request headers. this does not include post-method form data, file uploads, Etc ., but it does include the URL. in practice this resulted in a 413 error when a URL was significantly longer than 8,000 characters. this limitation can be easily removed. look for all occurrences of 16 × 1024 in daemon. PM and replace them with a larger value. of course, this does increase your exposure to denial of service attacks.

3. In addition, it is worth noting that when the href attribute of <a> is mentioned in some articles, the URL cannot exceed 1024 bytes, which is not verified in detail.

In summary, the URL is not suitable for too long, not a last resort. Try not to submit a large number of parameters through the GET method. You can consider using the POST method (about 2 m, it should be related to the server and settings ). In addition, such a long URL is quite unfriendly when accessing and adding to Favorites (some articles mention that some browsers may also encounter problems when adding too many URLs to favorites. Of course, the previously set database fields are still processed as 255bytes, And now you may want to expand it.

Refer:

1. What is the maximum length of a URL?
2. What is the limit on QueryString/GET/URL parameters?

Source: http://Jorkin.Reallydo.Com/default.asp? Id = 515