gotosocial/vendor/google.golang.org/grpc/internal/metadata/metadata.go

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2023-05-09 17:19:48 +00:00
/*
*
* Copyright 2020 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
// Package metadata contains functions to set and get metadata from addresses.
//
// This package is experimental.
package metadata
import (
"fmt"
"strings"
"google.golang.org/grpc/metadata"
"google.golang.org/grpc/resolver"
)
type mdKeyType string
const mdKey = mdKeyType("grpc.internal.address.metadata")
type mdValue metadata.MD
func (m mdValue) Equal(o interface{}) bool {
om, ok := o.(mdValue)
if !ok {
return false
}
if len(m) != len(om) {
return false
}
for k, v := range m {
ov := om[k]
if len(ov) != len(v) {
return false
}
for i, ve := range v {
if ov[i] != ve {
return false
}
}
}
return true
}
// Get returns the metadata of addr.
func Get(addr resolver.Address) metadata.MD {
attrs := addr.Attributes
if attrs == nil {
return nil
}
md, _ := attrs.Value(mdKey).(mdValue)
return metadata.MD(md)
}
// Set sets (overrides) the metadata in addr.
//
// When a SubConn is created with this address, the RPCs sent on it will all
// have this metadata.
func Set(addr resolver.Address, md metadata.MD) resolver.Address {
addr.Attributes = addr.Attributes.WithValue(mdKey, mdValue(md))
return addr
}
// Validate returns an error if the input md contains invalid keys or values.
//
// If the header is not a pseudo-header, the following items are checked:
// - header names must contain one or more characters from this set [0-9 a-z _ - .].
// - if the header-name ends with a "-bin" suffix, no validation of the header value is performed.
// - otherwise, the header value must contain one or more characters from the set [%x20-%x7E].
func Validate(md metadata.MD) error {
for k, vals := range md {
// pseudo-header will be ignored
if k[0] == ':' {
continue
}
// check key, for i that saving a conversion if not using for range
for i := 0; i < len(k); i++ {
r := k[i]
if !(r >= 'a' && r <= 'z') && !(r >= '0' && r <= '9') && r != '.' && r != '-' && r != '_' {
return fmt.Errorf("header key %q contains illegal characters not in [0-9a-z-_.]", k)
}
}
if strings.HasSuffix(k, "-bin") {
continue
}
// check value
for _, val := range vals {
if hasNotPrintable(val) {
return fmt.Errorf("header key %q contains value with non-printable ASCII characters", k)
}
}
}
return nil
}
// hasNotPrintable return true if msg contains any characters which are not in %x20-%x7E
func hasNotPrintable(msg string) bool {
// for i that saving a conversion if not using for range
for i := 0; i < len(msg); i++ {
if msg[i] < 0x20 || msg[i] > 0x7E {
return true
}
}
return false
}