99 lines
2.4 KiB
Go
99 lines
2.4 KiB
Go
package main
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import (
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"encoding/json"
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"errors"
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"fmt"
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"io"
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"net/http"
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"strconv"
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"strings"
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"github.com/julienschmidt/httprouter"
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)
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type envelope map[string]any
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func (app *application) readJSON(w http.ResponseWriter, r *http.Request, dest any) error {
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maxBytes := 1_048_576
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r.Body = http.MaxBytesReader(w, r.Body, int64(maxBytes))
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decoder := json.NewDecoder(r.Body)
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decoder.DisallowUnknownFields()
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err := decoder.Decode(dest)
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if err != nil {
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var syntaxError *json.SyntaxError
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var unmarshallError *json.UnmarshalTypeError
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var invalidUnmarshall *json.InvalidUnmarshalError
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var maxBytesError *http.MaxBytesError
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switch {
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case errors.As(err, &syntaxError):
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return fmt.Errorf("body contains badly-formed JSON (at character %d)", syntaxError.Offset)
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case errors.Is(err, io.ErrUnexpectedEOF):
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return errors.New("body contains badly-formed JSON")
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case errors.As(err, &unmarshallError):
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if unmarshallError.Field != "" {
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return fmt.Errorf("the body contains incorrect json type for field %q", unmarshallError.Field)
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}
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return fmt.Errorf("body contains incorrect JSON type (at character %d)", unmarshallError.Offset)
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case errors.Is(err, io.EOF):
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return errors.New("body must not be empty")
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case strings.HasPrefix(err.Error(), "json: unknown field "):
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fieldName := strings.TrimPrefix(err.Error(), "json: unknown field ")
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return fmt.Errorf("body contains uknown key %s", fieldName)
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case errors.As(err, &maxBytesError):
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return fmt.Errorf("body must not be larger than %d bytes", maxBytesError.Limit)
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case errors.As(err, &invalidUnmarshall):
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panic(err)
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default:
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return err
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}
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}
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err = decoder.Decode(&struct{}{})
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if err != io.EOF {
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return errors.New("body must only contain a single JSON value")
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}
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return nil // no errors
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}
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func (app *application) readIDParam(r *http.Request) (int64, error) {
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params := httprouter.ParamsFromContext(r.Context())
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id, err := strconv.ParseInt(params.ByName("id"), 10, 64)
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if err != nil || id < 1 {
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return 0, errors.New("invalid id parameter")
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}
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return id, nil
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}
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func (app *application) writeJSON(w http.ResponseWriter, status int, data any, headers http.Header) error {
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js, err := json.Marshal(data)
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if err != nil {
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return err
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}
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js = append(js, '\n')
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for key, value := range headers {
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w.Header()[key] = value
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}
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w.Header().Set("Content-Type", "application/json")
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w.WriteHeader(status)
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w.Write(js)
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return nil
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}
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