/*
*
* Copyright 2015, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
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* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
/**
* Metadata module
*
* This module defines the Metadata class, which represents header and trailer
* metadata for gRPC calls. Here is an example of how to use it:
*
* var metadata = new metadata_module.Metadata();
* metadata.set('key1', 'value1');
* metadata.add('key1', 'value2');
* metadata.get('key1') // returns ['value1', 'value2']
*
* @module
*/
'use strict';
var _ = require('lodash');
var grpc = require('./grpc_extension');
/**
* Class for storing metadata. Keys are normalized to lowercase ASCII.
* @constructor
*/
function Metadata() {
this._internal_repr = {};
}
function normalizeKey(key) {
key = key.toLowerCase();
if (grpc.metadataKeyIsLegal(key)) {
return key;
} else {
throw new Error('Metadata key"' + key + '" contains illegal characters');
}
}
function validate(key, value) {
if (grpc.metadataKeyIsBinary(key)) {
if (!(value instanceof Buffer)) {
throw new Error('keys that end with \'-bin\' must have Buffer values');
}
} else {
if (!_.isString(value)) {
throw new Error(
'keys that don\'t end with \'-bin\' must have String values');
}
if (!grpc.metadataNonbinValueIsLegal(value)) {
throw new Error('Metadata string value "' + value +
'" contains illegal characters');
}
}
}
/**
* Sets the given value for the given key, replacing any other values associated
* with that key. Normalizes the key.
* @param {String} key The key to set
* @param {String|Buffer} value The value to set. Must be a buffer if and only
* if the normalized key ends with '-bin'
*/
Metadata.prototype.set = function(key, value) {
key = normalizeKey(key);
validate(key, value);
this._internal_repr[key] = [value];
};
/**
* Adds the given value for the given key. Normalizes the key.
* @param {String} key The key to add to.
* @param {String|Buffer} value The value to add. Must be a buffer if and only
* if the normalized key ends with '-bin'
*/
Metadata.prototype.add = function(key, value) {
key = normalizeKey(key);
validate(key, value);
if (!this._internal_repr[key]) {
this._internal_repr[key] = [];
}
this._internal_repr[key].push(value);
};
/**
* Remove the given key and any associated values. Normalizes the key.
* @param {String} key The key to remove
*/
Metadata.prototype.remove = function(key) {
key = normalizeKey(key);
if (Object.prototype.hasOwnProperty.call(this._internal_repr, key)) {
delete this._internal_repr[key];
}
};
/**
* Gets a list of all values associated with the key. Normalizes the key.
* @param {String} key The key to get
* @return {Array.<String|Buffer>} The values associated with that key
*/
Metadata.prototype.get = function(key) {
key = normalizeKey(key);
if (Object.prototype.hasOwnProperty.call(this._internal_repr, key)) {
return this._internal_repr[key];
} else {
return [];
}
};
/**
* Get a map of each key to a single associated value. This reflects the most
* common way that people will want to see metadata.
* @return {Object.<String,String|Buffer>} A key/value mapping of the metadata
*/
Metadata.prototype.getMap = function() {
var result = {};
_.forOwn(this._internal_repr, function(values, key) {
if(values.length > 0) {
result[key] = values[0];
}
});
return result;
};
/**
* Clone the metadata object.
* @return {Metadata} The new cloned object
*/
Metadata.prototype.clone = function() {
var copy = new Metadata();
_.forOwn(this._internal_repr, function(value, key) {
copy._internal_repr[key] = _.clone(value);
});
return copy;
};
/**
* Gets the metadata in the format used by interal code. Intended for internal
* use only. API stability is not guaranteed.
* @private
* @return {Object.<String, Array.<String|Buffer>>} The metadata
*/
Metadata.prototype._getCoreRepresentation = function() {
return this._internal_repr;
};
/**
* Creates a Metadata object from a metadata map in the internal format.
* Intended for internal use only. API stability is not guaranteed.
* @private
* @param {Object.<String, Array.<String|Buffer>>} The metadata
* @return {Metadata} The new Metadata object
*/
Metadata._fromCoreRepresentation = function(metadata) {
var newMetadata = new Metadata();
if (metadata) {
_.forOwn(metadata, function(value, key) {
newMetadata._internal_repr[key] = _.clone(value);
});
}
return newMetadata;
};
module.exports = Metadata;