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"use strict";
// This is a subclass of Mongo, which stores both the default connection
// and the direct connection to a specific secondary node. For reads with
// readPreference "secondary", they are sent to the specific secondary node.
function SpecificSecondaryReaderMongo(host, secondary) {
var defaultMongo = new Mongo(host);
var secondaryMongo = new Mongo(secondary);
// This overrides the default runCommand() in Mongo
this.runCommand = function runCommand(dbName, commandObj, options) {
// If commandObj is specified with the readPreference "secondary", then use direct
// connection to secondary. Otherwise use the default connection.
if (commandObj.hasOwnProperty("$readPreference")) {
if (commandObj.$readPreference.mode === "secondary") {
return secondaryMongo.runCommand(dbName, commandObj, options);
}
}
return defaultMongo.runCommand(dbName, commandObj, options);
};
return new Proxy(this, {
get: function get(target, property, receiver) {
// If the property is defined on the SpecificSecondaryReaderMongo instance itself, then
// return it. Otherwise, get the value of the property from the Mongo instance.
if (target.hasOwnProperty(property)) {
return target[property];
}
var value = defaultMongo[property];
if (typeof value === "function") {
if (property === "getDB" || property === "startSession") {
// 'receiver' is the Proxy object.
return value.bind(receiver);
}
return value.bind(defaultMongo);
}
return value;
},
set: function set(target, property, value, receiver) {
// Delegate setting the value of any property to the Mongo instance so
// that it can be accessed in functions acting on the Mongo instance
// directly instead of this Proxy. For example, the "slaveOk" property
// needs to be set on the Mongo instance in order for the query options
// bit to be set correctly.
defaultMongo[property] = value;
return true;
},
});
}
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