Fins supports request breakpointing, which allows you to pause a request in flight and query and modify it. To enable breakpointing, add the following to your application's configuration file:
[application] breakpoint=1 breakpoint_port=12345
bash-2.05$ telnet buoy.riverweb.com 12345 Trying 204.97.242.43... Connected to buoy.riverweb.com. Escape character is '^]'. Welcome to Fins Breakpoint Service.
app->breakpoint("some description", (["id": id, "response": response ]));
Welcome to Fins Breakpoint Service. Breakpoint on test > id; (1) Result: Fins.HTTPRequest("GET" "/space/start/2006-04-25/2") > id->variables; (2) Result: ([ ]) > id->misc; (3) Result: ([ /* 5 elements */ "_session": Session(6d5581d44dab127d7fb1, ([ ])), "current_page": "start/2006-04-25/2", "current_page_object": object(230), "session_id": "6d5581d44dab127d7fb1", "session_variables": ([ ]) ]) > id->misc->current_page_object["title"]; (4) Result: "Collaborative editing for Mac: on sale, too!" > go Resuming.