112 lines
2.3 KiB
Go
112 lines
2.3 KiB
Go
|
package link
|
||
|
|
|
||
|
|
import (
|
||
|
|
"net/http"
|
||
|
|
"regexp"
|
||
|
|
"strings"
|
||
|
|
)
|
||
|
|
|
||
|
|
var (
|
||
|
|
commaRegexp = regexp.MustCompile(`,\s{0,}`)
|
||
|
|
valueCommaRegexp = regexp.MustCompile(`([^"]),`)
|
||
|
|
equalRegexp = regexp.MustCompile(` *= *`)
|
||
|
|
keyRegexp = regexp.MustCompile(`[a-z*]+`)
|
||
|
|
linkRegexp = regexp.MustCompile(`\A<(.+)>;(.+)\z`)
|
||
|
|
semiRegexp = regexp.MustCompile(`; +`)
|
||
|
|
valRegexp = regexp.MustCompile(`"+([^"]+)"+`)
|
||
|
|
)
|
||
|
|
|
||
|
|
// Group returned by Parse, contains multiple links indexed by "rel"
|
||
|
|
type Group map[string]*Link
|
||
|
|
|
||
|
|
// Link contains a Link item with URI, Rel, and other non-URI components in Extra.
|
||
|
|
type Link struct {
|
||
|
|
URI string
|
||
|
|
Rel string
|
||
|
|
Extra map[string]string
|
||
|
|
}
|
||
|
|
|
||
|
|
// String returns the URI
|
||
|
|
func (l *Link) String() string {
|
||
|
|
return l.URI
|
||
|
|
}
|
||
|
|
|
||
|
|
// ParseRequest parses the provided *http.Request into a Group
|
||
|
|
func ParseRequest(req *http.Request) Group {
|
||
|
|
if req == nil {
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
return ParseHeader(req.Header)
|
||
|
|
}
|
||
|
|
|
||
|
|
// ParseResponse parses the provided *http.Response into a Group
|
||
|
|
func ParseResponse(resp *http.Response) Group {
|
||
|
|
if resp == nil {
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
return ParseHeader(resp.Header)
|
||
|
|
}
|
||
|
|
|
||
|
|
// ParseHeader retrieves the Link header from the provided http.Header and parses it into a Group
|
||
|
|
func ParseHeader(h http.Header) Group {
|
||
|
|
if headers, found := h["Link"]; found {
|
||
|
|
return Parse(strings.Join(headers, ", "))
|
||
|
|
}
|
||
|
|
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// Parse parses the provided string into a Group
|
||
|
|
func Parse(s string) Group {
|
||
|
|
if s == "" {
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
s = valueCommaRegexp.ReplaceAllString(s, "$1")
|
||
|
|
|
||
|
|
group := Group{}
|
||
|
|
|
||
|
|
for _, l := range commaRegexp.Split(s, -1) {
|
||
|
|
linkMatches := linkRegexp.FindAllStringSubmatch(l, -1)
|
||
|
|
|
||
|
|
if len(linkMatches) == 0 {
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
pieces := linkMatches[0]
|
||
|
|
|
||
|
|
link := &Link{URI: pieces[1], Extra: map[string]string{}}
|
||
|
|
|
||
|
|
for _, extra := range semiRegexp.Split(pieces[2], -1) {
|
||
|
|
vals := equalRegexp.Split(extra, -1)
|
||
|
|
|
||
|
|
key := keyRegexp.FindString(vals[0])
|
||
|
|
val := valRegexp.FindStringSubmatch(vals[1])[1]
|
||
|
|
|
||
|
|
if key == "rel" {
|
||
|
|
vals := strings.Split(val, " ")
|
||
|
|
rels := []string{vals[0]}
|
||
|
|
|
||
|
|
if len(vals) > 1 {
|
||
|
|
for _, v := range vals[1:] {
|
||
|
|
if !strings.HasPrefix(v, "http") {
|
||
|
|
rels = append(rels, v)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
rel := strings.Join(rels, " ")
|
||
|
|
|
||
|
|
link.Rel = rel
|
||
|
|
group[rel] = link
|
||
|
|
} else {
|
||
|
|
link.Extra[key] = val
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return group
|
||
|
|
}
|