This is a robots.txt exclusion protocol implementation for Go language (golang).

To build and run tests run go test in source directory.

As usual, no special installation is required, just

import "github.com/temoto/robotstxt.go"

run go get and you're ready.

First of all, you need to parse robots.txt data. You can do it with functions FromBytes(body []byte) (*RobotsData, error) or same for string:

robots, err := robotstxt.FromBytes([]byte("User-agent: *\nDisallow:"))
robots, err := robotstxt.FromString("User-agent: *\nDisallow:")

As of 2012-10-03, FromBytes is the most efficient method, everything else is a wrapper for this core function.

There are few convenient constructors for various purposes:

• FromResponse(*http.Response) (*RobotsData, error) to init robots data

from HTTP response. It does not call response.Body.Close():

robots, err := robotstxt.FromResponse(resp)
resp.Body.Close()
if err != nil {
    log.Println("Error parsing robots.txt:", err.Error())
}

• FromStatusAndBytes(statusCode int, body []byte) (*RobotsData, error) or

FromStatusAndString if you prefer to read bytes (string) yourself. Passing status code applies following logic in line with Google's interpretation of robots.txt files:

• status 2xx -> parse body with FromBytes and apply rules listed there.
• status 4xx -> allow all (even 401/403, as recommended by Google).
• other (5xx) -> disallow all, consider this a temporary unavailability.

Parsing robots.txt content builds a kind of logic database, which you can query with (r *RobotsData) TestAgent(url, agent string) (bool).

Explicit passing of agent is useful if you want to query for different agents. For single agent users there is an efficient option: RobotsData.FindGroup(userAgent string) returns a structure with .Test(path string) method and .CrawlDelay time.Duration.

Simple query with explicit user agent. Each call will scan all rules.

allow := robots.TestAgent("/", "FooBot")

Or query several paths against same user agent for performance.

group := robots.FindGroup("BarBot")
group.Test("/")
group.Test("/download.mp3")
group.Test("/news/article-2012-1")

Honorable contributors (in undefined order):

• Ilya Grigorik (igrigorik)
• Martin Angers (PuerkitoBio)
• Micha Gorelick (mynameisfiber)

Initial commit and other: Sergey Shepelev [email protected]