Aneurin Barker Snook
90 lines
2.6 KiB
Go
90 lines
2.6 KiB
Go
package rest
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import (
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"net/http"
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)
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// Error represents a REST API error.
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// It can be marshaled to JSON with ease.
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type Error struct {
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StatusCode int `json:"statusCode"` // HTTP status code (200, 404, 500 etc.)
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Message string `json:"message"` // Status message ("OK", "Not found", "Internal server error" etc.)
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Data map[string]interface{} `json:"data,omitempty"` // Optional additional data.
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}
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// Error retrieves the message of a REST API Error.
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// If it has a "error" string attached using WithData or WithError, that message is returned.
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// Otherwise, the Error's own message is returned.
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func (e Error) Error() string {
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if e.Data != nil && e.Data["error"] != nil {
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if value, ok := e.Data["error"].(string); ok {
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return value
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}
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}
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return e.Message
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}
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// Is determines whether the Error is an instance of the target.
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// https://pkg.go.dev/errors#Is
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//
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// This function supports matching both any error and a specific error, based on the status code.
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// Use rest.Err (an empty error) for the former:
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//
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// errors.Is(err, rest.Err) // True if any REST API Error
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// errors.Is(err, rest.ErrBadRequest) // True if error is REST 400 Bad Request
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func (e Error) Is(target error) bool {
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t, ok := target.(Error)
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if !ok {
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return false
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}
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if t.StatusCode == 0 {
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return true
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}
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return t.StatusCode == e.StatusCode
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}
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// WithData returns a copy of the HTTP error with the given data merged in.
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func (e Error) WithData(data map[string]interface{}) Error {
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if e.Data == nil {
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e.Data = map[string]any{}
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}
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if data != nil {
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for key, value := range data {
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e.Data[key] = value
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}
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}
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return e
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}
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// WithError returns a copy of the HTTP error with the given error's message merged in to its additional data.
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func (e Error) WithError(err error) Error {
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return e.WithData(map[string]interface{}{
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"error": err.Error(),
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})
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}
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// WithMessage returns a copy of the HTTP error with the given message.
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func (e Error) WithMessage(message string) Error {
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e.Message = message
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return e
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}
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// WithValue returns a copy of the HTTP error with a single data value added.
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func (e Error) WithValue(name string, value any) Error {
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return e.WithData(map[string]any{
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name: value,
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})
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}
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// Write writes the HTTP error to an HTTP response as plain text.
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// Additional data is omitted.
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func (e Error) Write(w http.ResponseWriter) {
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w.WriteHeader(e.StatusCode)
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w.Write([]byte(e.Message))
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}
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// WriteJSON writes the HTTP error to an HTTP response as JSON.
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func (e Error) WriteJSON(w http.ResponseWriter) error {
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return WriteResponseJSON(w, e.StatusCode, e)
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}
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