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Using the C++ client library
Description: How to use the C++ client library to talk to the warehouseTutorial Level: BEGINNER
Contents
Example code
The warehouse_ros package provides a C++ ROS client library to the DB. For now, we just have an example of use. Note that this requires the db server to be running, as described in the previous tutorial.
https://raw.githubusercontent.com/ros-planning/warehouse_ros/indigo-devel/test/test_mongo_ros.cpp
1 #include "test_mongo_helpers.h"
2 #include <mongo_ros/message_collection.h>
3 #include <mongo_ros/exceptions.h>
4 #include <ros/ros.h>
5 #include <boost/foreach.hpp>
6 #include <gtest/gtest.h>
7
8 namespace mr=mongo_ros;
9 namespace gm=geometry_msgs;
10 using std::vector;
11 using std::string;
12 using std::cout;
13
14 typedef mr::MessageWithMetadata<gm::Pose> PoseWithMetadata;
15 typedef PoseWithMetadata::ConstPtr PoseMetaPtr;
16
17 // Helper function that creates metadata for a message.
18 // Here we'll use the x and y position, as well as a 'name'
19 // field that isn't part of the original message.
20 mr::Metadata makeMetadata (const gm::Pose& p, const string& v)
21 {
22 return mr::Metadata("x", p.position.x, "y", p.position.y, "name", v);
23 }
24
25 TEST(MongoRos, MongoRos)
26 {
27 // Symbols used in queries to denote binary predicates for < and >
28 // Note that equality is the default, so we don't need a symbol for it
29 using mr::LT;
30 using mr::GT;
31
32 // Clear existing data if any
33 mr::dropDatabase("my_db", "localhost", 27019, 60.0);
34
35 // Set up db
36 mr::MessageCollection<gm::Pose> coll("my_db", "poses", "localhost",
37 27019, 60.0);
38
39 // Arrange to index on metadata fields 'x' and 'name'
40 coll.ensureIndex("name");
41 coll.ensureIndex("x");
42
43 // Add some poses and metadata
44 const gm::Pose p1 = makePose(24, 42, 0);
45 const gm::Pose p2 = makePose(10, 532, 3);
46 const gm::Pose p3 = makePose(53, 22, 5);
47 const gm::Pose p4 = makePose(22, -5, 33);
48 coll.insert(p1, makeMetadata(p1, "bar"));
49 coll.insert(p2, makeMetadata(p2, "baz"));
50 coll.insert(p3, makeMetadata(p3, "qux"));
51 coll.insert(p1, makeMetadata(p1, "oof"));
52 coll.insert(p4, makeMetadata(p4, "ooof"));
53 EXPECT_EQ(5u, coll.count());
54
55 // Simple query: find the pose with name 'qux' and return just its metadata
56 // Since we're doing an equality check, we don't explicitly specify a predicate
57 vector<PoseMetaPtr> res = coll.pullAllResults(mr::Query("name", "qux"), true);
58 EXPECT_EQ(1u, res.size());
59 EXPECT_EQ("qux", res[0]->lookupString("name"));
60 EXPECT_DOUBLE_EQ(53, res[0]->lookupDouble("x"));
61
62 // Set up query: position.x < 40 and position.y > 0. Reverse order
63 // by the "name" metadata field. Also, here we pull the message itself, not
64 // just the metadata. Finally, we can't use the simplified construction
65 // syntax here because it's too long
66 mr::Query q = mr::Query().append("x", mr::LT, 40).append("y", mr::GT, 0);
67 vector<PoseMetaPtr> poses = coll.pullAllResults(q, false, "name", false);
68
69 // Verify poses.
70 EXPECT_EQ(3u, poses.size());
71 EXPECT_EQ(p1, *poses[0]);
72 EXPECT_EQ(p2, *poses[1]);
73 EXPECT_EQ(p1, *poses[2]);
74
75 EXPECT_EQ("oof", poses[0]->lookupString("name"));
76 EXPECT_EQ("baz", poses[1]->lookupString("name"));
77 EXPECT_EQ("bar", poses[2]->lookupString("name"));
78
79 // Set up query to delete some poses.
80 mr::Query q2 ("y", mr::LT, 30);
81
82 EXPECT_EQ(5u, coll.count());
83 EXPECT_EQ(2u, coll.removeMessages(q2));
84 EXPECT_EQ(3u, coll.count());
85
86 // Test findOne
87 mr::Query q4("name", "bar");
88 EXPECT_EQ(p1, *coll.findOne(q4, false));
89 EXPECT_DOUBLE_EQ(24, coll.findOne(q4, true)->lookupDouble("x"));
90
91 mr::Query q5("name", "barbar");
92 EXPECT_THROW(coll.findOne(q5, true), mr::NoMatchingMessageException);
93 EXPECT_THROW(coll.findOne(q5, false), mr::NoMatchingMessageException);
94
95 // Test update
96 coll.modifyMetadata(q4, mr::Metadata("name", "barbar"));
97 EXPECT_EQ(3u, coll.count());
98 EXPECT_THROW(coll.findOne(q4, false), mr::NoMatchingMessageException);
99 ROS_INFO("here");
100 EXPECT_EQ(p1, *coll.findOne(q5, false));
101
102 // Check stored metadata
103 boost::shared_ptr<mongo::DBClientConnection> conn =
104 mr::makeDbConnection(ros::NodeHandle());
105 EXPECT_EQ("geometry_msgs/Pose", mr::messageType(*conn, "my_db", "poses"));
106 }
107
108
109 int main (int argc, char** argv)
110 {
111 ros::init(argc, argv, "client_test");
112 ros::NodeHandle nh;
113 testing::InitGoogleTest(&argc, argv);
114 return RUN_ALL_TESTS();
115 }
116
