123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132 |
- /*
- *
- * 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 validates every pair in md with ValidatePair.
- func Validate(md metadata.MD) error {
- for k, vals := range md {
- if err := ValidatePair(k, vals...); err != nil {
- return err
- }
- }
- 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
- }
- // ValidatePair validate a key-value pair with the following rules (the pseudo-header will be skipped) :
- //
- // - key must contain one or more characters.
- // - the characters in the key must be contained in [0-9 a-z _ - .].
- // - if the key ends with a "-bin" suffix, no validation of the corresponding value is performed.
- // - the characters in the every value must be printable (in [%x20-%x7E]).
- func ValidatePair(key string, vals ...string) error {
- // key should not be empty
- if key == "" {
- return fmt.Errorf("there is an empty key in the header")
- }
- // pseudo-header will be ignored
- if key[0] == ':' {
- return nil
- }
- // check key, for i that saving a conversion if not using for range
- for i := 0; i < len(key); i++ {
- r := key[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-_.]", key)
- }
- }
- if strings.HasSuffix(key, "-bin") {
- return nil
- }
- // check value
- for _, val := range vals {
- if hasNotPrintable(val) {
- return fmt.Errorf("header key %q contains value with non-printable ASCII characters", key)
- }
- }
- return nil
- }
|