owncast/utils/restendpointhelper.go

69 lines
2.1 KiB
Go

package utils
import (
"errors"
"fmt"
"net/http"
"strings"
)
const restURLPatternHeaderKey = "Owncast-Resturl-Pattern"
// takes the segment pattern of an Url string and returns the segment before the first dynamic REST parameter.
func getPatternForRestEndpoint(pattern string) string {
firstIndex := strings.Index(pattern, "/{")
if firstIndex == -1 {
return pattern
}
return strings.TrimRight(pattern[:firstIndex], "/") + "/"
}
func zip2D(iterable1 *[]string, iterable2 *[]string) map[string]string {
var dict = make(map[string]string)
for index, key := range *iterable1 {
dict[key] = (*iterable2)[index]
}
return dict
}
func mapPatternWithRequestURL(pattern string, requestURL string) (map[string]string, error) {
patternSplit := strings.Split(pattern, "/")
requestURLSplit := strings.Split(requestURL, "/")
if len(patternSplit) == len(requestURLSplit) {
return zip2D(&patternSplit, &requestURLSplit), nil
}
return nil, errors.New("the length of pattern and request Url does not match")
}
func readParameter(pattern string, requestURL string, paramName string) (string, error) {
all, err := mapPatternWithRequestURL(pattern, requestURL)
if err != nil {
return "", err
}
if value, exists := all[fmt.Sprintf("{%s}", paramName)]; exists {
return value, nil
}
return "", fmt.Errorf("parameter with name %s not found", paramName)
}
// ReadRestURLParameter will return the parameter from the request of the requested name.
func ReadRestURLParameter(r *http.Request, parameterName string) (string, error) {
pattern, found := r.Header[restURLPatternHeaderKey]
if !found {
return "", fmt.Errorf("this HandlerFunc is not marked as REST-Endpoint. Cannot read Parameter '%s' from Request", parameterName)
}
return readParameter(pattern[0], r.URL.Path, parameterName)
}
// RestEndpoint wraps a handler to use the rest endpoint helper.
func RestEndpoint(pattern string, handler http.HandlerFunc) (string, http.HandlerFunc) {
baseURL := getPatternForRestEndpoint(pattern)
return baseURL, func(w http.ResponseWriter, r *http.Request) {
r.Header[restURLPatternHeaderKey] = []string{pattern}
handler(w, r)
}
}