linkheader

README

# Golang Link Header Parser

Library for parsing HTTP Link headers. Requires Go 1.6 or higher.

Docs can be found on [the GoDoc page](https://godoc.org/github.com/tomnomnom/linkheader).

[![Build Status](https://travis-ci.org/tomnomnom/linkheader.svg)](https://travis-ci.org/tomnomnom/linkheader)

## Basic Example

```go
package main

import (
	"fmt"

	"github.com/tomnomnom/linkheader"
)

func main() {
	header := "<https://api.github.com/user/58276/repos?page=2>; rel=\"next\"," +
		"<https://api.github.com/user/58276/repos?page=2>; rel=\"last\""
	links := linkheader.Parse(header)

	for _, link := range links {
		fmt.Printf("URL: %s; Rel: %s\n", link.URL, link.Rel)
	}
}

// Output:
// URL: https://api.github.com/user/58276/repos?page=2; Rel: next
// URL: https://api.github.com/user/58276/repos?page=2; Rel: last
```

Documentation

Overview

Package linkheader provides functions for parsing HTTP Link headers

Index

• type Link
  • func (l Link) HasParam(key string) bool
  • func (l Link) Param(key string) string
  • func (l Link) String() string
• type Links
  • func Parse(raw string) Links
  • func ParseMultiple(headers []string) Links
  • func (l Links) FilterByRel(r string) Links
  • func (l Links) String() string

Examples

• Link.String
• Links.FilterByRel
• Links.String
• Parse
• ParseMultiple

Types

type Link

type Link struct {
	URL    string
	Rel    string
	Params map[string]string
}

A Link is a single URL and related parameters

func (Link) HasParam

func (l Link) HasParam(key string) bool

HasParam returns if a Link has a particular parameter or not

func (Link) Param

func (l Link) Param(key string) string

Param returns the value of a parameter if it exists

func (Link) String

func (l Link) String() string

String returns the string representation of a link

Example

package main

import (
	"fmt"

	"github.com/tomnomnom/linkheader"
)

func main() {
	link := linkheader.Link{
		URL: "http://example.com/page/2",
		Rel: "next",
	}

	fmt.Printf("Link: %s\n", link.String())

}

Output:

Link: <http://example.com/page/2>; rel="next"

type Links

type Links []Link

Links is a slice of Link structs

func Parse

func Parse(raw string) Links

Parse parses a raw Link header in the form:

<url>; rel="foo", <url>; rel="bar"; wat="dis"

returning a slice of Link structs

Example

package main

import (
	"fmt"

	"github.com/tomnomnom/linkheader"
)

func main() {
	header := "<https://api.github.com/user/58276/repos?page=2>; rel=\"next\"," +
		"<https://api.github.com/user/58276/repos?page=2>; rel=\"last\""
	links := linkheader.Parse(header)

	for _, link := range links {
		fmt.Printf("URL: %s; Rel: %s\n", link.URL, link.Rel)
	}

}

Output:

URL: https://api.github.com/user/58276/repos?page=2; Rel: next
URL: https://api.github.com/user/58276/repos?page=2; Rel: last

func ParseMultiple

func ParseMultiple(headers []string) Links

ParseMultiple is like Parse, but accepts a slice of headers rather than just one header string

Example

package main

import (
	"fmt"

	"github.com/tomnomnom/linkheader"
)

func main() {
	headers := []string{
		"<https://api.github.com/user/58276/repos?page=2>; rel=\"next\"",
		"<https://api.github.com/user/58276/repos?page=2>; rel=\"last\"",
	}
	links := linkheader.ParseMultiple(headers)

	for _, link := range links {
		fmt.Printf("URL: %s; Rel: %s\n", link.URL, link.Rel)
	}

}

Output:

URL: https://api.github.com/user/58276/repos?page=2; Rel: next
URL: https://api.github.com/user/58276/repos?page=2; Rel: last

func (Links) FilterByRel

func (l Links) FilterByRel(r string) Links

FilterByRel filters a group of Links by the provided Rel attribute

Example

package main

import (
	"fmt"

	"github.com/tomnomnom/linkheader"
)

func main() {
	header := "<https://api.github.com/user/58276/repos?page=2>; rel=\"next\"," +
		"<https://api.github.com/user/58276/repos?page=2>; rel=\"last\""
	links := linkheader.Parse(header)

	for _, link := range links.FilterByRel("last") {
		fmt.Printf("URL: %s; Rel: %s\n", link.URL, link.Rel)
	}

}

Output:

URL: https://api.github.com/user/58276/repos?page=2; Rel: last

func (Links) String

func (l Links) String() string

String returns the string representation of multiple Links for use in HTTP responses etc

Example

package main

import (
	"fmt"

	"github.com/tomnomnom/linkheader"
)

func main() {

	links := linkheader.Links{
		{URL: "http://example.com/page/3", Rel: "next"},
		{URL: "http://example.com/page/1", Rel: "last"},
	}

	fmt.Printf("Link: %s\n", links.String())

}

Output:

Link: <http://example.com/page/3>; rel="next", <http://example.com/page/1>; rel="last"