3 files changed, 98 insertions, 3 deletions

diff --git a/src/mongo/client/mongo_uri.cpp b/src/mongo/client/mongo_uri.cpp
index 597933712df..c8b76e776a8 100644
--- a/src/mongo/client/mongo_uri.cpp
+++ b/src/mongo/client/mongo_uri.cpp
@@ -40,6 +40,7 @@
 #include <boost/algorithm/string/classification.hpp>
 #include <boost/algorithm/string/find_iterator.hpp>
 #include <boost/algorithm/string/predicate.hpp>
+#include <boost/range/algorithm/count.hpp>
 
 #include "mongo/base/status_with.h"
 #include "mongo/bson/bsonobjbuilder.h"
@@ -56,8 +57,6 @@ using namespace std::literals::string_literals;
 namespace {
 constexpr std::array<char, 16> hexits{
     '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
-const mongo::StringData kURIPrefix{"mongodb://"};
-const mongo::StringData kURISRVPrefix{"mongodb+srv://"};
 
 // This vector must remain sorted.  It is over pairs to facilitate a call to `std::includes` using
 // a `std::map<std::string, std::string>` as the other parameter.
@@ -112,6 +111,10 @@ namespace mongo {
 
 namespace {
 
+constexpr StringData kURIPrefix = "mongodb://"_sd;
+constexpr StringData kURISRVPrefix = "mongodb+srv://"_sd;
+constexpr StringData kDefaultMongoHost = "127.0.0.1:27017"_sd;
+
 /**
  * Helper Method for MongoURI::parse() to split a string into exactly 2 pieces by a char
  * delimiter.
@@ -519,8 +522,53 @@ const boost::optional<std::string> MongoURI::getAppName() const {
     const auto optIter = _options.find("appName");
     if (optIter != end(_options)) {
         return optIter->second;
+    }
+    return boost::none;
+}
+
+std::string MongoURI::canonicalizeURIAsString() const {
+    StringBuilder uri;
+    uri << kURIPrefix;
+    if (!_user.empty()) {
+        uri << uriEncode(_user);
+        if (!_password.empty()) {
+            uri << ":" << uriEncode(_password);
+        }
+        uri << "@";
+    }
+
+    const auto& servers = _connectString.getServers();
+    if (!servers.empty()) {
+        auto delimeter = "";
+        for (auto& hostAndPort : servers) {
+            if (boost::count(hostAndPort.host(), ':') > 1) {
+                uri << delimeter << "[" << uriEncode(hostAndPort.host()) << "]"
+                    << ":" << uriEncode(std::to_string(hostAndPort.port()));
+            } else if (StringData(hostAndPort.host()).endsWith(".sock")) {
+                uri << delimeter << uriEncode(hostAndPort.host());
+            } else {
+                uri << delimeter << uriEncode(hostAndPort.host()) << ":"
+                    << uriEncode(std::to_string(hostAndPort.port()));
+            }
+            delimeter = ",";
+        }
     } else {
-        return boost::none;
+        uri << kDefaultMongoHost;
+    }
+
+    uri << "/";
+    if (!_database.empty()) {
+        uri << uriEncode(_database);
+    }
+
+    if (!_options.empty()) {
+        auto delimeter = "";
+        uri << "?";
+        for (const auto& pair : _options) {
+            uri << delimeter << uriEncode(pair.first) << "=" << uriEncode(pair.second);
+            delimeter = "&";
+        }
     }
+    return uri.str();
 }
 }  // namespace mongo
diff --git a/src/mongo/client/mongo_uri.h b/src/mongo/client/mongo_uri.h
index 9b61dcaebd9..c121fa21801 100644
--- a/src/mongo/client/mongo_uri.h
+++ b/src/mongo/client/mongo_uri.h
@@ -130,22 +130,64 @@ public:
         return _user;
     }
 
+    void setUser(std::string newUsername) {
+        _user = std::move(newUsername);
+    }
+
     const std::string& getPassword() const {
         return _password;
     }
 
+    void setPassword(std::string newPassword) {
+        _password = std::move(newPassword);
+    }
+
     const OptionsMap& getOptions() const {
         return _options;
     }
 
+    void addOption(std::string newKey, std::string newValue) {
+        _options[std::move(newKey)] = std::move(newValue);
+    }
+
+    void setOptionIfNecessary(std::string uriParamKey, std::string value) {
+        const auto key = _options.find(uriParamKey);
+        if (key == end(_options) && !value.empty()) {
+            addOption(uriParamKey, value);
+        }
+    }
+
+    boost::optional<std::string> getOption(const std::string& key) const {
+        const auto optIter = _options.find(key);
+        if (optIter != end(_options)) {
+            return optIter->second;
+        }
+        return boost::none;
+    }
+
     const std::string& getDatabase() const {
         return _database;
     }
 
+    std::string getAuthenticationDatabase() {
+        auto authDB = _options.find("authSource");
+        if (authDB != _options.end()) {
+            return authDB->second;
+        } else if (!_database.empty()) {
+            return _database;
+        } else {
+            return "admin";
+        }
+    }
+
     bool isValid() const {
         return _connectString.isValid();
     }
 
+    const ConnectionString& connectionString() const {
+        return _connectString;
+    }
+
     const std::string& toString() const {
         return _connectString.toString();
     }
@@ -161,6 +203,9 @@ public:
 
     const boost::optional<std::string> getAppName() const;
 
+    std::string canonicalizeURIAsString() const;
+
+
     boost::optional<bool> getRetryWrites() const {
         return _retryWrites;
     }
diff --git a/src/mongo/client/replica_set_monitor.cpp b/src/mongo/client/replica_set_monitor.cpp
index 769358dc9b0..0488b9100ec 100644
--- a/src/mongo/client/replica_set_monitor.cpp
+++ b/src/mongo/client/replica_set_monitor.cpp
@@ -854,6 +854,8 @@ HostAndPort Refresher::_refreshUntilMatches(const ReadPreferenceSetting* criteri
 
                 if (_set->setUri.isValid()) {
                     targetURI = _set->setUri.cloneURIForServer(ns.host);
+                    targetURI.setUser("");
+                    targetURI.setPassword("");
                 } else {
                     targetURI = MongoURI(ConnectionString(ns.host));
                 }