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