132 lines
3.1 KiB
Markdown
132 lines
3.1 KiB
Markdown
justcaptcha ver. 2.0.2
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======================
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A simple CAPTCHA service implementation.
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## Service usage
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justcaptchad -expiry 10m -listen /var/run/justcaptcha/sock
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`-expiry` takes time for CAPTCHA to be valid for in format X{s,m,h}.
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`-listen` is `ip:port` or `/path/to/unix.sock` to listen on.
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## Service HTTP API
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### Errors
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All error codes are returned with an error message in `text/plain`.
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### Create a new CAPTCHA
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POST /
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It will return an ID of a new CAPTCHA in `text/plain`.
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#### HTTP codes
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- `201` if created (always being created)
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### Get an image for a CAPTCHA
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GET /:captcha_id/image?style=
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Responds with an image in JPEG format (`image/jpeg`).
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An optional URL parameter `style=` set a name of a CAPTCHA style if it is
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supported by CAPTCHA implementation.
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#### HTTP codes
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- `200` if exists
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- `404` if doesn't exist
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- `500` if for some reason an image wasn't created
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### Submit an answer
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POST /:captcha_id
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Accepts `application/x-www-form-urlencoded` content type.
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It takes one parameter `answer=123456`.
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Responds with an empty body and one of the HTTP codes.
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#### HTTP codes
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- `202` if solved
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- `403` if not solved
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### Check if captcha is solved
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GET /:captcha_id?remove
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Responds with an empty body and one of the HTTP codes.
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If an optional `remove` parameter without a value supplied CAPTCHA will be
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removed without checking and a HTTP code `204` will be sent. Otherwise, a `403`
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HTTP code will be sent if it is not solved.
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A `remove` parameter was added because browsers will print an error in a console
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if HTTP code is not within `2xx`, so to keep a console clean you can provide
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this parameter.
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This can be useful to remove an unused CAPTCHA from a DB without waiting for it
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to be expired. E.g. when a visitor requests for a new CAPTCHA or leaving a page.
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#### HTTP codes
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- `204` if solved
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- `403` if not solved
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### Example of interaction
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First a client makes a POST request with empty body to create a new CAPTCHA and obtains an ID for it.
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POST /
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As a result we get an ID `n60f2K9JiD5c4qX9MYe90A54nT0nnJrtgfhAjfaWtBg`.
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Then a client requests an image for a new CAPTCHA. E.g. with a dark style.
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GET /n60f2K9JiD5c4qX9MYe90A54nT0nnJrtgfhAjfaWtBg/image?style=dark
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Then a client submits an answer for a CAPTCHA.
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POST 'answer=198807' /n60f2K9JiD5c4qX9MYe90A54nT0nnJrtgfhAjfaWtBg
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And if answer was correct a client gets a HTTP code 202. Or 403 otherwise.
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Then a server checks if CAPTCHA was solved with following request.
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GET /n60f2K9JiD5c4qX9MYe90A54nT0nnJrtgfhAjfaWtBg
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## Library usage
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A simple example using built-in dwelling CAPTCHA implementation.
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Create a new CAPTCHA:
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c := dwcaptcha.NewDwellingCaptcha(expiry)
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_, id := inmemdb.New(someAdditionalDataUsedInIDGenerationUsuallyIPAddr, c)
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Get an image for a CAPTCHA:
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i := inmemdb.Image(captchaID, captchaStyle)
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if i == nil {
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... // error handling
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}
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jpeg.Encode(w, *i, &jpeg.Options{Quality: 20})
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Solve a CAPTCHA:
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if ok := inmemdb.Solve(captchaID, answer); !ok {
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... // not solved
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}
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// solved
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...
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Check is CAPTCHA was solved:
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if ok := inmemdb.IsSolved(captchaID); !ok {
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... // not solved
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}
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// solved
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... |