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