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https://gitlab.com/pulsechaincom/prysm-pulse.git
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a005c77b3f
* rely on errors.Is * wrap errors
54 lines
1.3 KiB
Go
54 lines
1.3 KiB
Go
package prometheus
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import (
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"bytes"
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"encoding/json"
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"fmt"
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"net/http"
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"github.com/golang/gddo/httputil"
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)
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const (
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contentTypePlainText = "text/plain"
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contentTypeJSON = "application/json"
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)
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// generatedResponse is a container for response output.
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type generatedResponse struct {
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// Err is protocol error, if any.
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Err string `json:"error"`
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// Data is response output, if any.
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Data interface{} `json:"data"`
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}
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// negotiateContentType parses "Accept:" header and returns preferred content type string.
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func negotiateContentType(r *http.Request) string {
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contentTypes := []string{
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contentTypePlainText,
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contentTypeJSON,
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}
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return httputil.NegotiateContentType(r, contentTypes, contentTypePlainText)
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}
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// writeResponse is content-type aware response writer.
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func writeResponse(w http.ResponseWriter, r *http.Request, response generatedResponse) error {
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switch negotiateContentType(r) {
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case contentTypePlainText:
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buf, ok := response.Data.(bytes.Buffer)
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if !ok {
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return fmt.Errorf("unexpected data: %v", response.Data)
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}
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if _, err := w.Write(buf.Bytes()); err != nil {
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return fmt.Errorf("could not write response body: %w", err)
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}
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case contentTypeJSON:
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w.Header().Set("Content-Type", contentTypeJSON)
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if err := json.NewEncoder(w).Encode(response); err != nil {
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return err
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}
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}
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return nil
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}
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