mirror of https://github.com/caddyserver/caddy.git
106 lines
2.8 KiB
Go
106 lines
2.8 KiB
Go
package caddyhttp
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import (
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"fmt"
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mathrand "math/rand"
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"path"
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"runtime"
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"strings"
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"github.com/caddyserver/caddy"
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)
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// Error is a convenient way for a Handler to populate the
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// essential fields of a HandlerError. If err is itself a
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// HandlerError, then any essential fields that are not
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// set will be populated.
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func Error(statusCode int, err error) HandlerError {
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const idLen = 9
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if he, ok := err.(HandlerError); ok {
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if he.ID == "" {
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he.ID = randString(idLen, true)
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}
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if he.Trace == "" {
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he.Trace = trace()
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}
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if he.StatusCode == 0 {
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he.StatusCode = statusCode
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}
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return he
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}
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return HandlerError{
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ID: randString(idLen, true),
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StatusCode: statusCode,
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Err: err,
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Trace: trace(),
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}
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}
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// HandlerError is a serializable representation of
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// an error from within an HTTP handler.
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type HandlerError struct {
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Err error // the original error value and message
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StatusCode int // the HTTP status code to associate with this error
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Message string // an optional message that can be shown to the user
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Recommendations []string // an optional list of things to try to resolve the error
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ID string // generated; for identifying this error in logs
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Trace string // produced from call stack
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}
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func (e HandlerError) Error() string {
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var s string
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if e.ID != "" {
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s += fmt.Sprintf("{id=%s}", e.ID)
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}
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if e.Trace != "" {
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s += " " + e.Trace
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}
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if e.StatusCode != 0 {
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s += fmt.Sprintf(": HTTP %d", e.StatusCode)
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}
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if e.Err != nil {
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s += ": " + e.Err.Error()
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}
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return strings.TrimSpace(s)
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}
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// randString returns a string of n random characters.
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// It is not even remotely secure OR a proper distribution.
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// But it's good enough for some things. It excludes certain
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// confusing characters like I, l, 1, 0, O, etc. If sameCase
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// is true, then uppercase letters are excluded.
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func randString(n int, sameCase bool) string {
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if n <= 0 {
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return ""
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}
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dict := []byte("abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRTUVWXY23456789")
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if sameCase {
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dict = []byte("abcdefghijkmnpqrstuvwxyz0123456789")
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}
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b := make([]byte, n)
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for i := range b {
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b[i] = dict[mathrand.Int63()%int64(len(dict))]
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}
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return string(b)
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}
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func trace() string {
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if pc, file, line, ok := runtime.Caller(2); ok {
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filename := path.Base(file)
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pkgAndFuncName := path.Base(runtime.FuncForPC(pc).Name())
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return fmt.Sprintf("%s (%s:%d)", pkgAndFuncName, filename, line)
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}
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return ""
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}
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// ErrRehandle is a special error value that Handlers should return
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// from their ServeHTTP() method if the request is to be re-processed.
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// This error value is a sentinel value that should not be wrapped or
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// modified.
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var ErrRehandle = fmt.Errorf("rehandling request")
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// ErrorCtxKey is the context key to use when storing
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// an error (for use with context.Context).
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const ErrorCtxKey = caddy.CtxKey("handler_chain_error")
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