Filters (2)

• Filters should adhere to the Unix philosophy: simple tools that do one simple thing and do it well

• Each header filter:

  • is only called once, with a reference to the HTTP::Headers object

  • can modify the message headers

• Each body filter:

  • is called each time a chunk of data is received

  • can modify the data on the fly

• The proxy passes the possibly modified chunk on to the next filter in the stack

• In the end, the proxy sends the modified chunk to the client

• But not all filters are applied on all connections!