110 lines
2.4 KiB
Go
110 lines
2.4 KiB
Go
package redirect
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import (
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"net/http"
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"net/url"
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"regexp"
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"github.com/vulcand/oxy/v2/utils"
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"go.opentelemetry.io/otel/trace"
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)
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const (
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schemeHTTP = "http"
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schemeHTTPS = "https"
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)
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const typeName = "Redirect"
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var uriRegexp = regexp.MustCompile(`^(https?):\/\/(\[[\w:.]+\]|[\w\._-]+)?(:\d+)?(.*)$`)
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type redirect struct {
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next http.Handler
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regex *regexp.Regexp
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replacement string
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permanent bool
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errHandler utils.ErrorHandler
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name string
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rawURL func(*http.Request) string
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}
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// New creates a Redirect middleware.
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func newRedirect(next http.Handler, regex, replacement string, permanent bool, rawURL func(*http.Request) string, name string) (http.Handler, error) {
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re, err := regexp.Compile(regex)
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if err != nil {
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return nil, err
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}
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return &redirect{
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regex: re,
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replacement: replacement,
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permanent: permanent,
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errHandler: utils.DefaultHandler,
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next: next,
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name: name,
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rawURL: rawURL,
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}, nil
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}
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func (r *redirect) GetTracingInformation() (string, string, trace.SpanKind) {
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return r.name, typeName, trace.SpanKindInternal
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}
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func (r *redirect) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
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oldURL := r.rawURL(req)
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// If the Regexp doesn't match, skip to the next handler.
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if !r.regex.MatchString(oldURL) {
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r.next.ServeHTTP(rw, req)
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return
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}
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// Apply a rewrite regexp to the URL.
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newURL := r.regex.ReplaceAllString(oldURL, r.replacement)
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// Parse the rewritten URL and replace request URL with it.
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parsedURL, err := url.Parse(newURL)
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if err != nil {
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r.errHandler.ServeHTTP(rw, req, err)
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return
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}
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if newURL != oldURL {
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handler := &moveHandler{location: parsedURL, permanent: r.permanent}
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handler.ServeHTTP(rw, req)
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return
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}
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req.URL = parsedURL
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// Make sure the request URI corresponds the rewritten URL.
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req.RequestURI = req.URL.RequestURI()
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r.next.ServeHTTP(rw, req)
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}
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type moveHandler struct {
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location *url.URL
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permanent bool
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}
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func (m *moveHandler) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
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rw.Header().Set("Location", m.location.String())
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status := http.StatusFound
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if req.Method != http.MethodGet {
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status = http.StatusTemporaryRedirect
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}
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if m.permanent {
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status = http.StatusMovedPermanently
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if req.Method != http.MethodGet {
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status = http.StatusPermanentRedirect
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}
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}
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rw.WriteHeader(status)
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_, err := rw.Write([]byte(http.StatusText(status)))
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if err != nil {
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http.Error(rw, err.Error(), http.StatusInternalServerError)
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}
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}
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