3 ms·

Will every request to a worker-enabled site, pass through the worker v8 engine and charged at the going rate, even requests for static ressources like favicons,

by btb 9y ago

Will every request to a worker-enabled site, pass through the worker v8 engine and charged at the going rate, even requests for static ressources like favicons, or jpgs etc? Or is there some way to limit the worker engine request matching to a specific area of your site(like /service)?

kentonv 9y ago
You can specify URL patterns where the worker should be enabled or disabled, under "routes" in the config UI. You won't be billed for requests to routes where the worker is disabled.
- jbergstroem 9y ago
  I wish routing and page rules had rudimentary regex support like VCL or most other location matching route libraries/servers.
  - kentonv 9y ago
    Yeah, trouble is, it's depressingly easy to create a regex that performs very poorly, so if we allowed that, people could easily break the service. However! One of the neat things about Workers is that you totally can use regexes in JavaScript, and our sandbox prevents runaway CPU usage. So if you really wanted regex-based page rules before, you can probably get that with a Worker. We've exposed an API for controlling Cloudflare features from a Worker, including many things commonly controlled via page rules: https://developers.cloudflare.com/workers/reference/cloudflare-features/ https://developers.cloudflare.com/workers/reference/cloudfla... We'll be adding more in the future.
    - derefr 9y ago
      > a regex that performs very poorly Would that still be true if you limited the regex support to DFAs instead of NFAs? I can’t think of a single use-case for backreferences in routing patterns. :)
      - osteele 9y ago
        Good idea; a nit on terminology: NFAs and DFAs have equivalent expressive power[1]. For this application, you probably want a determinized DFA (one without epsilon transitions); that's constant time on the input string. (It's still not as fast as Boyer-Moore.) Backrefs let you write PDAs, which are more powerful than either NFAs or DFAs. PCRE2[2] implements DFA-based matching. The cited page says it's slower than the NFA algorithm (although presumably a lower complexity order); I think because of lookaheads and capturing. [1] Michael Sipser, _Introduction to the Theory of Computation_. [2] http://www.pcre.org/current/doc/html/pcre2matching.html http://www.pcre.org/current/doc/html/pcre2matching.html
        derefr 9y ago
        > determinized DFA Yep, that's the thing I was thinking of. Thanks! Question, since you seem like you might know: is there an alternative regex library—or a plain Yacc parsing grammar that you could stick as a validator in front of PCRE's parser—that would allow through only the regexes which parse out to constant-time (determinized) DFAs?
        skybrian 9y ago
        Not an expert in this, but I'm thinking this is usually handled by switching to a non-backtracking regexp engine. Otherwise, any such validator would depend on details of the regexp engine's implementation.

by btb 9y ago

kentonv 9y ago

You can specify URL patterns where the worker should be enabled or disabled, under "routes" in the config UI. You won't be billed for requests to routes where the worker is disabled.

jbergstroem 9y ago
I wish routing and page rules had rudimentary regex support like VCL or most other location matching route libraries/servers.
- kentonv 9y ago
  Yeah, trouble is, it's depressingly easy to create a regex that performs very poorly, so if we allowed that, people could easily break the service. However! One of the neat things about Workers is that you totally can use regexes in JavaScript, and our sandbox prevents runaway CPU usage. So if you really wanted regex-based page rules before, you can probably get that with a Worker. We've exposed an API for controlling Cloudflare features from a Worker, including many things commonly controlled via page rules: https://developers.cloudflare.com/workers/reference/cloudflare-features/ https://developers.cloudflare.com/workers/reference/cloudfla... We'll be adding more in the future.
  - derefr 9y ago
    > a regex that performs very poorly Would that still be true if you limited the regex support to DFAs instead of NFAs? I can’t think of a single use-case for backreferences in routing patterns. :)
    - osteele 9y ago
      Good idea; a nit on terminology: NFAs and DFAs have equivalent expressive power[1]. For this application, you probably want a determinized DFA (one without epsilon transitions); that's constant time on the input string. (It's still not as fast as Boyer-Moore.) Backrefs let you write PDAs, which are more powerful than either NFAs or DFAs. PCRE2[2] implements DFA-based matching. The cited page says it's slower than the NFA algorithm (although presumably a lower complexity order); I think because of lookaheads and capturing. [1] Michael Sipser, _Introduction to the Theory of Computation_. [2] http://www.pcre.org/current/doc/html/pcre2matching.html http://www.pcre.org/current/doc/html/pcre2matching.html
      - derefr 9y ago
        > determinized DFA Yep, that's the thing I was thinking of. Thanks! Question, since you seem like you might know: is there an alternative regex library—or a plain Yacc parsing grammar that you could stick as a validator in front of PCRE's parser—that would allow through only the regexes which parse out to constant-time (determinized) DFAs?
        skybrian 9y ago
        Not an expert in this, but I'm thinking this is usually handled by switching to a non-backtracking regexp engine. Otherwise, any such validator would depend on details of the regexp engine's implementation.