URL Valid Resource?



Received URL Valid?


  • User-agent of header request
  • Referer of header request
  • IP of request
  • Expiry of url
When you send HTTP request -> Extracting HTML -> receive URL.
Is This URL Valid?

Something URL Resource closely related with sent Request.
And URL Resource default is valid on some catch conditions.

But also often that: this url is public and valid.

We are only talking about:

  1. URL Resource closely related with sent Request.
  2. URL Resource default is valid on some catch conditions.

1. URL Resource closely related with sent Request

Req 1 => .... => Receive: URL A.

Req 2 -->  |
Req 3 -->  |  URL A
Req 4 -->  |

Server A check Ip and block req 2, req 3, .. => create "Leech URL" on server (where send Req 1)
URL A has expiry date => req2, req3, .. need sooner.

2. URL Resource default is valid on some catch conditions.

URL A is valid when header "referer" of request is a condition value.

Eg:
REQUEST 1 send to URL A, Server A procced and then return URL of resource: URL B. URL B valid if request has header referer A

Why is this important?
Because: sometimes url of resource has format:
/<ip>_<id of resource>_<extra option> (but this is encode.)
Some experienced programmer can decode and has "navtive function":
f(id resource, force option) => url resource.
This url is powerful if: its server not check "referer" of request header.

Please wait next!


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