113 lines
2.9 KiB
Go
113 lines
2.9 KiB
Go
// Package apiutils contains utilities which are useful for implementing api
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// endpoints.
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package apiutils
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import (
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"context"
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"crypto/rand"
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"encoding/hex"
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"encoding/json"
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"errors"
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"fmt"
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"net/http"
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"strconv"
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"github.com/mediocregopher/mediocre-go-lib/v2/mlog"
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)
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type loggerCtxKey int
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// SetRequestLogger sets the given Logger onto the given Request's Context,
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// returning a copy.
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func SetRequestLogger(r *http.Request, logger *mlog.Logger) *http.Request {
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ctx := r.Context()
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ctx = context.WithValue(ctx, loggerCtxKey(0), logger)
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return r.WithContext(ctx)
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}
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// GetRequestLogger returns the Logger which was set by SetRequestLogger onto
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// this Request, or nil.
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func GetRequestLogger(r *http.Request) *mlog.Logger {
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ctx := r.Context()
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logger, _ := ctx.Value(loggerCtxKey(0)).(*mlog.Logger)
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if logger == nil {
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logger = mlog.Null
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}
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return logger
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}
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// JSONResult writes the JSON encoding of the given value as the response body.
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func JSONResult(rw http.ResponseWriter, r *http.Request, v interface{}) {
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b, err := json.Marshal(v)
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if err != nil {
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InternalServerError(rw, r, err)
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return
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}
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b = append(b, '\n')
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rw.Header().Set("Content-Type", "application/json")
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rw.Write(b)
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}
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// BadRequest writes a 400 status and a JSON encoded error struct containing the
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// given error as the response body.
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func BadRequest(rw http.ResponseWriter, r *http.Request, err error) {
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GetRequestLogger(r).Warn(r.Context(), "bad request", err)
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rw.WriteHeader(400)
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JSONResult(rw, r, struct {
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Error string `json:"error"`
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}{
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Error: err.Error(),
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})
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}
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// InternalServerError writes a 500 status and a JSON encoded error struct
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// containing a generic error as the response body (though it will log the given
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// one).
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func InternalServerError(rw http.ResponseWriter, r *http.Request, err error) {
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GetRequestLogger(r).Error(r.Context(), "internal server error", err)
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rw.WriteHeader(500)
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JSONResult(rw, r, struct {
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Error string `json:"error"`
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}{
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Error: "internal server error",
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})
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}
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// StrToInt parses the given string as an integer, or returns the given default
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// integer if the string is empty.
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func StrToInt(str string, defaultVal int) (int, error) {
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if str == "" {
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return defaultVal, nil
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}
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return strconv.Atoi(str)
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}
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// GetCookie returns the namd cookie's value, or the given default value if the
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// cookie is not set.
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//
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// This will only return an error if there was an unexpected error parsing the
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// Request's cookies.
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func GetCookie(r *http.Request, cookieName, defaultVal string) (string, error) {
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c, err := r.Cookie(cookieName)
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if errors.Is(err, http.ErrNoCookie) {
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return defaultVal, nil
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} else if err != nil {
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return "", fmt.Errorf("reading cookie %q: %w", cookieName, err)
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}
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return c.Value, nil
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}
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// RandStr returns a human-readable random string with the given number of bytes
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// of randomness.
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func RandStr(numBytes int) string {
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b := make([]byte, numBytes)
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if _, err := rand.Read(b); err != nil {
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panic(err)
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}
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return hex.EncodeToString(b)
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}
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