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| -rw-r--r-- | grpc-common/node/route_guide/README.md | 362 | ||||
| -rw-r--r-- | grpc-common/node/route_guide/route_guide.proto | 120 | ||||
| -rw-r--r-- | grpc-common/node/route_guide/route_guide_client.js | 231 | ||||
| -rw-r--r-- | grpc-common/node/route_guide/route_guide_db.json | 601 | ||||
| -rw-r--r-- | grpc-common/node/route_guide/route_guide_server.js | 249 |
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diff --git a/grpc-common/node/route_guide/README.md b/grpc-common/node/route_guide/README.md new file mode 100644 index 0000000000..5460c9905d --- /dev/null +++ b/grpc-common/node/route_guide/README.md @@ -0,0 +1,362 @@ +#gRPC Basics: Node.js + +This tutorial provides a basic Node.js programmer's introduction to working with gRPC. By walking through this example you'll learn how to: + +- Define a service in a .proto file. +- Use the Node.js gRPC API to write a simple client and server for your service. + +It assumes that you have read the [Getting started](https://github.com/grpc/grpc-common) guide and are familiar with [protocol buffers] (https://developers.google.com/protocol-buffers/docs/overview). Note that the example in this tutorial uses the proto3 version of the protocol buffers language, which is currently in alpha release:you can find out more in the [proto3 language guide](https://developers.google.com/protocol-buffers/docs/proto3) and see the [release notes](https://github.com/google/protobuf/releases) for the new version in the protocol buffers Github repository. + +This isn't a comprehensive guide to using gRPC in Node.js: more reference documentation is coming soon. + +## Why use gRPC? + +Our example is a simple route mapping application that lets clients get information about features on their route, create a summary of their route, and exchange route information such as traffic updates with the server and other clients. + +With gRPC we can define our service once in a .proto file and implement clients and servers in any of gRPC's supported languages, which in turn can be run in environments ranging from servers inside Google to your own tablet - all the complexity of communication between different languages and environments is handled for you by gRPC. We also get all the advantages of working with protocol buffers, including efficient serialization, a simple IDL, and easy interface updating. + +## Example code and setup + +The example code for our tutorial is in [grpc/grpc-common/node/route_guide](https://github.com/grpc/grpc-common/tree/master/node/route_guide). To download the example, clone the `grpc-common` repository by running the following command: +```shell +$ git clone https://github.com/grpc/grpc-common.git +``` + +Then change your current directory to `grpc-common/node/route_guide`: +```shell +$ cd grpc-common/node/route_guide +``` + +You also should have the relevant tools installed to generate the server and client interface code - if you don't already, follow the setup instructions in [the Node.js quick start guide](https://github.com/grpc/grpc-common/tree/master/node). + + +## Defining the service + +Our first step (as you'll know from [Getting started](https://github.com/grpc/grpc-common)) is to define the gRPC *service* and the method *request* and *response* types using [protocol buffers] (https://developers.google.com/protocol-buffers/docs/overview). You can see the complete .proto file in [`grpc-common/protos/route_guide.proto`](https://github.com/grpc/grpc-common/blob/master/protos/route_guide.proto). + +To define a service, you specify a named `service` in your .proto file: + +```protobuf +service RouteGuide { + ... +} +``` + +Then you define `rpc` methods inside your service definition, specifying their request and response types. gRPC lets you define four kinds of service method, all of which are used in the `RouteGuide` service: + +- A *simple RPC* where the client sends a request to the server using the stub and waits for a response to come back, just like a normal function call. +```protobuf + // Obtains the feature at a given position. + rpc GetFeature(Point) returns (Feature) {} +``` + +- A *server-side streaming RPC* where the client sends a request to the server and gets a stream to read a sequence of messages back. The client reads from the returned stream until there are no more messages. As you can see in our example, you specify a server-side streaming method by placing the `stream` keyword before the *response* type. +```protobuf + // Obtains the Features available within the given Rectangle. Results are + // streamed rather than returned at once (e.g. in a response message with a + // repeated field), as the rectangle may cover a large area and contain a + // huge number of features. + rpc ListFeatures(Rectangle) returns (stream Feature) {} +``` + +- A *client-side streaming RPC* where the client writes a sequence of messages and sends them to the server, again using a provided stream. Once the client has finished writing the messages, it waits for the server to read them all and return its response. You specify a server-side streaming method by placing the `stream` keyword before the *request* type. +```protobuf + // Accepts a stream of Points on a route being traversed, returning a + // RouteSummary when traversal is completed. + rpc RecordRoute(stream Point) returns (RouteSummary) {} +``` + +- A *bidirectional streaming RPC* where both sides send a sequence of messages using a read-write stream. The two streams operate independently, so clients and servers can read and write in whatever order they like: for example, the server could wait to receive all the client messages before writing its responses, or it could alternately read a message then write a message, or some other combination of reads and writes. The order of messages in each stream is preserved. You specify this type of method by placing the `stream` keyword before both the request and the response. +```protobuf + // Accepts a stream of RouteNotes sent while a route is being traversed, + // while receiving other RouteNotes (e.g. from other users). + rpc RouteChat(stream RouteNote) returns (stream RouteNote) {} +``` + +Our .proto file also contains protocol buffer message type definitions for all the request and response types used in our service methods - for example, here's the `Point` message type: +```protobuf +// Points are represented as latitude-longitude pairs in the E7 representation +// (degrees multiplied by 10**7 and rounded to the nearest integer). +// Latitudes should be in the range +/- 90 degrees and longitude should be in +// the range +/- 180 degrees (inclusive). +message Point { + int32 latitude = 1; + int32 longitude = 2; +} +``` + + +## Loading service descriptors from proto files + +The Node.js library dynamically generates service descriptors and client stub definitions from `.proto` files loaded at runtime. + +To load a `.proto` file, simply `require` the gRPC library, then use its `load()` method: + +```node +var grpc = require('grpc'); +var protoDescriptor = grpc.load(__dirname + '/route_guide.proto'); +// The protoDescriptor object has the full package hierarchy +var example = protoDescriptor.examples; +``` + +Once you've done this, the stub constructor is in the `examples` namespace (`protoDescriptor.examples.RouteGuide`) and the service descriptor (which is used to create a server) is a property of the stub (`protoDescriptor.examples.RouteGuide.service`); + +<a name="server"></a> +## Creating the server + +First let's look at how we create a `RouteGuide` server. If you're only interested in creating gRPC clients, you can skip this section and go straight to [Creating the client](#client) (though you might find it interesting anyway!). + +There are two parts to making our `RouteGuide` service do its job: +- Implementing the service interface generated from our service definition: doing the actual "work" of our service. +- Running a gRPC server to listen for requests from clients and return the service responses. + +You can find our example `RouteGuide` server in [grpc-common/node/route_guide/route_guide_server.js](https://github.com/grpc/grpc-common/blob/master/node/route_guide/route_guide_server.js). Let's take a closer look at how it works. + +### Implementing RouteGuide + +As you can see, our server has a `Server` constructor generated from the `RouteGuide.service` descriptor object + +```node +var Server = grpc.buildServer([examples.RouteGuide.service]); +``` +In this case we're implementing the *asynchronous* version of `RouteGuide`, which provides our default gRPC server behaviour. + +The functions in `route_guide_server.js` implement all our service methods. Let's look at the simplest type first, `getFeature`, which just gets a `Point` from the client and returns the corresponding feature information from its database in a `Feature`. + +```node +function checkFeature(point) { + var feature; + // Check if there is already a feature object for the given point + for (var i = 0; i < feature_list.length; i++) { + feature = feature_list[i]; + if (feature.location.latitude === point.latitude && + feature.location.longitude === point.longitude) { + return feature; + } + } + var name = ''; + feature = { + name: name, + location: point + }; + return feature; +} +function getFeature(call, callback) { + callback(null, checkFeature(call.request)); +} +``` + +The method is passed a call object for the RPC, which has the `Point` parameter as a property, and a callback to which we can pass our returned `Feature`. In the method body we populate a `Feature` corresponding to the given point and pass it to the callback, with a null first parameter to indicate that there is no error. + +Now let's look at something a bit more complicated - a streaming RPC. `listFeatures` is a server-side streaming RPC, so we need to send back multiple `Feature`s to our client. + +```node +function listFeatures(call) { + var lo = call.request.lo; + var hi = call.request.hi; + var left = _.min([lo.longitude, hi.longitude]); + var right = _.max([lo.longitude, hi.longitude]); + var top = _.max([lo.latitude, hi.latitude]); + var bottom = _.min([lo.latitude, hi.latitude]); + // For each feature, check if it is in the given bounding box + _.each(feature_list, function(feature) { + if (feature.name === '') { + return; + } + if (feature.location.longitude >= left && + feature.location.longitude <= right && + feature.location.latitude >= bottom && + feature.location.latitude <= top) { + call.write(feature); + } + }); + call.end(); +} +``` + +As you can see, instead of getting the call object and callback in our method parameters, this time we get a `call` object that implements the `Writable` interface. In the method, we create as many `Feature` objects as we need to return, writing them to the `call` using its `write()` method. Finally, we call `call.end()` to indicate that we have sent all messages. + +If you look at the client-side streaming method `RecordRoute` you'll see it's quite similar to the unary call, except this time the `call` parameter implements the `Reader` interface. The `call`'s `'data'` event fires every time there is new data, and the `'end'` event fires when all data has been read. Like the unary case, we respond by calling the callback + +```node +call.on('data', function(point) { + // Process user data +}); +call.on('end', function() { + callback(null, result); +}); +``` + +Finally, let's look at our bidirectional streaming RPC `RouteChat()`. + +```node +function routeChat(call) { + call.on('data', function(note) { + var key = pointKey(note.location); + /* For each note sent, respond with all previous notes that correspond to + * the same point */ + if (route_notes.hasOwnProperty(key)) { + _.each(route_notes[key], function(note) { + call.write(note); + }); + } else { + route_notes[key] = []; + } + // Then add the new note to the list + route_notes[key].push(JSON.parse(JSON.stringify(note))); + }); + call.on('end', function() { + call.end(); + }); +} +``` + +This time we get a `call` implementing `Duplex` that can be used to read *and* write messages. The syntax for reading and writing here is exactly the same as for our client-streaming and server-streaming methods. Although each side will always get the other's messages in the order they were written, both the client and server can read and write in any order — the streams operate completely independently. + +### Starting the server + +Once we've implemented all our methods, we also need to start up a gRPC server so that clients can actually use our service. The following snippet shows how we do this for our `RouteGuide` service: + +```node +function getServer() { + return new Server({ + 'examples.RouteGuide' : { + getFeature: getFeature, + listFeatures: listFeatures, + recordRoute: recordRoute, + routeChat: routeChat + } + }); +} +var routeServer = getServer(); +routeServer.bind('0.0.0.0:50051'); +routeServer.listen(); +``` + +As you can see, we build and start our server with the following steps: + + 1. Create a `Server` constructor from the `RouteGuide` service descriptor. + 2. Implement the service methods. + 3. Create an instance of the server by calling the `Server` constructor with the method implementations. + 4. Specify the address and port we want to use to listen for client requests using the instance's `bind()` method. + 5. Call `listen()` on the instance to start the RPC server. + +<a name="client"></a> +## Creating the client + +In this section, we'll look at creating a Node.js client for our `RouteGuide` service. You can see our complete example client code in [grpc-common/node/route_guide/route_guide_client.js](https://github.com/grpc/grpc-common/blob/master/node/route_guide/route_guide_client.js). + +### Creating a stub + +To call service methods, we first need to create a *stub*. To do this, we just need to call the RouteGuide stub constructor, specifying the server address and port. + +```node +new example.RouteGuide('localhost:50051'); +``` + +### Calling service methods + +Now let's look at how we call our service methods. Note that all of these methods are asynchronous: they use either events or callbacks to retrieve results. + +#### Simple RPC + +Calling the simple RPC `GetFeature` is nearly as straightforward as calling a local asynchronous method. + +```node +var point = {latitude: 409146138, longitude: -746188906}; +stub.getFeature(point, function(err, feature) { + if (err) { + // process error + } else { + // process feature + } +}); +``` + +As you can see, we create and populate a request object. Finally, we call the method on the stub, passing it the request and callback. If there is no error, then we can read the response information from the server from our response object. + +```node + console.log('Found feature called "' + feature.name + '" at ' + + feature.location.latitude/COORD_FACTOR + ', ' + + feature.location.longitude/COORD_FACTOR); +``` + +#### Streaming RPCs + +Now let's look at our streaming methods. If you've already read [Creating the server](#server) some of this may look very familiar - streaming RPCs are implemented in a similar way on both sides. Here's where we call the server-side streaming method `ListFeatures`, which returns a stream of geographical `Feature`s: + +```node +var call = client.listFeatures(rectangle); + call.on('data', function(feature) { + console.log('Found feature called "' + feature.name + '" at ' + + feature.location.latitude/COORD_FACTOR + ', ' + + feature.location.longitude/COORD_FACTOR); + }); + call.on('end', function() { + // The server has finished sending + }); + call.on('status', function(status) { + // process status + }); +``` + +Instead of passing the method a request and callback, we pass it a request and get a `Readable` stream object back. The client can use the `Readable`'s `'data'` event to read the server's responses. This event fires with each `Feature` message object until there are no more messages: the `'end'` event indicates that the call is done. Finally, the status event fires when the server sends the status. + +The client-side streaming method `RecordRoute` is similar, except there we pass the method a callback and get back a `Writable`. + +```node + var call = client.recordRoute(function(error, stats) { + if (error) { + callback(error); + } + console.log('Finished trip with', stats.point_count, 'points'); + console.log('Passed', stats.feature_count, 'features'); + console.log('Travelled', stats.distance, 'meters'); + console.log('It took', stats.elapsed_time, 'seconds'); + }); + function pointSender(lat, lng) { + return function(callback) { + console.log('Visiting point ' + lat/COORD_FACTOR + ', ' + + lng/COORD_FACTOR); + call.write({ + latitude: lat, + longitude: lng + }); + _.delay(callback, _.random(500, 1500)); + }; + } + var point_senders = []; + for (var i = 0; i < num_points; i++) { + var rand_point = feature_list[_.random(0, feature_list.length - 1)]; + point_senders[i] = pointSender(rand_point.location.latitude, + rand_point.location.longitude); + } + async.series(point_senders, function() { + call.end(); + }); +``` + +Once we've finished writing our client's requests to the stream using `write()`, we need to call `end()` on the stream to let gRPC know that we've finished writing. If the status is `OK`, the `stats` object will be populated with the server's response. + +Finally, let's look at our bidirectional streaming RPC `routeChat()`. In this case, we just pass a context to the method and get back a `Duplex` stream object, which we can use to both write and read messages. + +```node +var call = client.routeChat(); +``` + +The syntax for reading and writing here is exactly the same as for our client-streaming and server-streaming methods. Although each side will always get the other's messages in the order they were written, both the client and server can read and write in any order — the streams operate completely independently. + +## Try it out! + +Build client and server: +```shell +$ npm install +``` +Run the server, which will listen on port 50051: +```shell +$ node ./route_guide_server.js --db_path=route_guide_db.json +``` +Run the client (in a different terminal): +```shell +$ node ./route_guide_client.js --db_path=route_guide_db.json +``` diff --git a/grpc-common/node/route_guide/route_guide.proto b/grpc-common/node/route_guide/route_guide.proto new file mode 100644 index 0000000000..442112823e --- /dev/null +++ b/grpc-common/node/route_guide/route_guide.proto @@ -0,0 +1,120 @@ +// 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. +// * Neither the name of Google Inc. nor the names of its +// 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 +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +syntax = "proto3"; + +option java_package = "io.grpc.examples"; + +package examples; + +// Interface exported by the server. +service RouteGuide { + // A simple RPC. + // + // Obtains the feature at a given position. + rpc GetFeature(Point) returns (Feature) {} + + // A server-to-client streaming RPC. + // + // Obtains the Features available within the given Rectangle. Results are + // streamed rather than returned at once (e.g. in a response message with a + // repeated field), as the rectangle may cover a large area and contain a + // huge number of features. + rpc ListFeatures(Rectangle) returns (stream Feature) {} + + // A client-to-server streaming RPC. + // + // Accepts a stream of Points on a route being traversed, returning a + // RouteSummary when traversal is completed. + rpc RecordRoute(stream Point) returns (RouteSummary) {} + + // A Bidirectional streaming RPC. + // + // Accepts a stream of RouteNotes sent while a route is being traversed, + // while receiving other RouteNotes (e.g. from other users). + rpc RouteChat(stream RouteNote) returns (stream RouteNote) {} +} + +// Points are represented as latitude-longitude pairs in the E7 representation +// (degrees multiplied by 10**7 and rounded to the nearest integer). +// Latitudes should be in the range +/- 90 degrees and longitude should be in +// the range +/- 180 degrees (inclusive). +message Point { + optional int32 latitude = 1; + optional int32 longitude = 2; +} + +// A latitude-longitude rectangle, represented as two diagonally opposite +// points "lo" and "hi". +message Rectangle { + // One corner of the rectangle. + optional Point lo = 1; + + // The other corner of the rectangle. + optional Point hi = 2; +} + +// A feature names something at a given point. +// +// If a feature could not be named, the name is empty. +message Feature { + // The name of the feature. + optional string name = 1; + + // The point where the feature is detected. + optional Point location = 2; +} + +// A RouteNote is a message sent while at a given point. +message RouteNote { + // The location from which the message is sent. + optional Point location = 1; + + // The message to be sent. + optional string message = 2; +} + +// A RouteSummary is received in response to a RecordRoute rpc. +// +// It contains the number of individual points received, the number of +// detected features, and the total distance covered as the cumulative sum of +// the distance between each point. +message RouteSummary { + // The number of points received. + optional int32 point_count = 1; + + // The number of known features passed while traversing the route. + optional int32 feature_count = 2; + + // The distance covered in metres. + optional int32 distance = 3; + + // The duration of the traversal in seconds. + optional int32 elapsed_time = 4; +} diff --git a/grpc-common/node/route_guide/route_guide_client.js b/grpc-common/node/route_guide/route_guide_client.js new file mode 100644 index 0000000000..60c47a429d --- /dev/null +++ b/grpc-common/node/route_guide/route_guide_client.js @@ -0,0 +1,231 @@ +// 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. +// * Neither the name of Google Inc. nor the names of its +// 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 +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +var async = require('async'); +var fs = require('fs'); +var parseArgs = require('minimist'); +var path = require('path'); +var _ = require('underscore'); +var grpc = require('grpc'); +var examples = grpc.load(__dirname + '/route_guide.proto').examples; +var client = new examples.RouteGuide('localhost:50051'); + +var COORD_FACTOR = 1e7; + +/** + * Run the getFeature demo. Calls getFeature with a point known to have a + * feature and a point known not to have a feature. + * @param {function} callback Called when this demo is complete + */ +function runGetFeature(callback) { + var next = _.after(2, callback); + function featureCallback(error, feature) { + if (error) { + callback(error); + } + if (feature.name === '') { + console.log('Found no feature at ' + + feature.location.latitude/COORD_FACTOR + ', ' + + feature.location.longitude/COORD_FACTOR); + } else { + console.log('Found feature called "' + feature.name + '" at ' + + feature.location.latitude/COORD_FACTOR + ', ' + + feature.location.longitude/COORD_FACTOR); + } + next(); + } + var point1 = { + latitude: 409146138, + longitude: -746188906 + }; + var point2 = { + latitude: 0, + longitude: 0 + }; + client.getFeature(point1, featureCallback); + client.getFeature(point2, featureCallback); +} + +/** + * Run the listFeatures demo. Calls listFeatures with a rectangle containing all + * of the features in the pre-generated database. Prints each response as it + * comes in. + * @param {function} callback Called when this demo is complete + */ +function runListFeatures(callback) { + var rectangle = { + lo: { + latitude: 400000000, + longitude: -750000000 + }, + hi: { + latitude: 420000000, + longitude: -730000000 + } + }; + console.log('Looking for features between 40, -75 and 42, -73'); + var call = client.listFeatures(rectangle); + call.on('data', function(feature) { + console.log('Found feature called "' + feature.name + '" at ' + + feature.location.latitude/COORD_FACTOR + ', ' + + feature.location.longitude/COORD_FACTOR); + }); + call.on('end', callback); +} + +/** + * Run the recordRoute demo. Sends several randomly chosen points from the + * pre-generated feature database with a variable delay in between. Prints the + * statistics when they are sent from the server. + * @param {function} callback Called when this demo is complete + */ +function runRecordRoute(callback) { + var argv = parseArgs(process.argv, { + string: 'db_path' + }); + fs.readFile(path.resolve(argv.db_path), function(err, data) { + if (err) callback(err); + var feature_list = JSON.parse(data); + + var num_points = 10; + var call = client.recordRoute(function(error, stats) { + if (error) { + callback(error); + } + console.log('Finished trip with', stats.point_count, 'points'); + console.log('Passed', stats.feature_count, 'features'); + console.log('Travelled', stats.distance, 'meters'); + console.log('It took', stats.elapsed_time, 'seconds'); + callback(); + }); + /** + * Constructs a function that asynchronously sends the given point and then + * delays sending its callback + * @param {number} lat The latitude to send + * @param {number} lng The longitude to send + * @return {function(function)} The function that sends the point + */ + function pointSender(lat, lng) { + /** + * Sends the point, then calls the callback after a delay + * @param {function} callback Called when complete + */ + return function(callback) { + console.log('Visiting point ' + lat/COORD_FACTOR + ', ' + + lng/COORD_FACTOR); + call.write({ + latitude: lat, + longitude: lng + }); + _.delay(callback, _.random(500, 1500)); + }; + } + var point_senders = []; + for (var i = 0; i < num_points; i++) { + var rand_point = feature_list[_.random(0, feature_list.length - 1)]; + point_senders[i] = pointSender(rand_point.location.latitude, + rand_point.location.longitude); + } + async.series(point_senders, function() { + call.end(); + }); + }); +} + +/** + * Run the routeChat demo. Send some chat messages, and print any chat messages + * that are sent from the server. + * @param {function} callback Called when the demo is complete + */ +function runRouteChat(callback) { + var call = client.routeChat(); + call.on('data', function(note) { + console.log('Got message "' + note.message + '" at ' + + note.location.latitude + ', ' + note.location.longitude); + }); + + call.on('end', callback); + + var notes = [{ + location: { + latitude: 0, + longitude: 0 + }, + message: 'First message' + }, { + location: { + latitude: 0, + longitude: 1 + }, + message: 'Second message' + }, { + location: { + latitude: 1, + longitude: 0 + }, + message: 'Third message' + }, { + location: { + latitude: 0, + longitude: 0 + }, + message: 'Fourth message' + }]; + for (var i = 0; i < notes.length; i++) { + var note = notes[i]; + console.log('Sending message "' + note.message + '" at ' + + note.location.latitude + ', ' + note.location.longitude); + call.write(note); + } + call.end(); +} + +/** + * Run all of the demos in order + */ +function main() { + async.series([ + runGetFeature, + runListFeatures, + runRecordRoute, + runRouteChat + ]); +} + +if (require.main === module) { + main(); +} + +exports.runGetFeature = runGetFeature; + +exports.runListFeatures = runListFeatures; + +exports.runRecordRoute = runRecordRoute; + +exports.runRouteChat = runRouteChat; diff --git a/grpc-common/node/route_guide/route_guide_db.json b/grpc-common/node/route_guide/route_guide_db.json new file mode 100644 index 0000000000..9d6a980ab7 --- /dev/null +++ b/grpc-common/node/route_guide/route_guide_db.json @@ -0,0 +1,601 @@ +[{ + "location": { + "latitude": 407838351, + "longitude": -746143763 + }, + "name": "Patriots Path, Mendham, NJ 07945, USA" +}, { + "location": { + "latitude": 408122808, + "longitude": -743999179 + }, + "name": "101 New Jersey 10, Whippany, NJ 07981, USA" +}, { + "location": { + "latitude": 413628156, + "longitude": -749015468 + }, + "name": "U.S. 6, Shohola, PA 18458, 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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. +// * Neither the name of Google Inc. nor the names of its +// 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 +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +var fs = require('fs'); +var parseArgs = require('minimist'); +var path = require('path'); +var _ = require('underscore'); +var grpc = require('grpc'); +var examples = grpc.load(__dirname + '/route_guide.proto').examples; + +var Server = grpc.buildServer([examples.RouteGuide.service]); + +var COORD_FACTOR = 1e7; + +/** + * For simplicity, a point is a record type that looks like + * {latitude: number, longitude: number}, and a feature is a record type that + * looks like {name: string, location: point}. feature objects with name==='' + * are points with no feature. + */ + +/** + * List of feature objects at points that have been requested so far. + */ +var feature_list = []; + +/** + * Get a feature object at the given point, or creates one if it does not exist. + * @param {point} point The point to check + * @return {feature} The feature object at the point. Note that an empty name + * indicates no feature + */ +function checkFeature(point) { + var feature; + // Check if there is already a feature object for the given point + for (var i = 0; i < feature_list.length; i++) { + feature = feature_list[i]; + if (feature.location.latitude === point.latitude && + feature.location.longitude === point.longitude) { + return feature; + } + } + var name = ''; + feature = { + name: name, + location: point + }; + return feature; +} + +/** + * getFeature request handler. Gets a request with a point, and responds with a + * feature object indicating whether there is a feature at that point. + * @param {EventEmitter} call Call object for the handler to process + * @param {function(Error, feature)} callback Response callback + */ +function getFeature(call, callback) { + callback(null, checkFeature(call.request)); +} + +/** + * listFeatures request handler. Gets a request with two points, and responds + * with a stream of all features in the bounding box defined by those points. + * @param {Writable} call Writable stream for responses with an additional + * request property for the request value. + */ +function listFeatures(call) { + var lo = call.request.lo; + var hi = call.request.hi; + var left = _.min([lo.longitude, hi.longitude]); + var right = _.max([lo.longitude, hi.longitude]); + var top = _.max([lo.latitude, hi.latitude]); + var bottom = _.min([lo.latitude, hi.latitude]); + // For each feature, check if it is in the given bounding box + _.each(feature_list, function(feature) { + if (feature.name === '') { + return; + } + if (feature.location.longitude >= left && + feature.location.longitude <= right && + feature.location.latitude >= bottom && + feature.location.latitude <= top) { + call.write(feature); + } + }); + call.end(); +} + +/** + * Calculate the distance between two points using the "haversine" formula. + * This code was taken from http://www.movable-type.co.uk/scripts/latlong.html. + * @param start The starting point + * @param end The end point + * @return The distance between the points in meters + */ +function getDistance(start, end) { + function toRadians(num) { + return num * Math.PI / 180; + } + var lat1 = start.latitude / COORD_FACTOR; + var lat2 = end.latitude / COORD_FACTOR; + var lon1 = start.longitude / COORD_FACTOR; + var lon2 = end.longitude / COORD_FACTOR; + var R = 6371000; // metres + var φ1 = toRadians(lat1); + var φ2 = toRadians(lat2); + var Δφ = toRadians(lat2-lat1); + var Δλ = toRadians(lon2-lon1); + + var a = Math.sin(Δφ/2) * Math.sin(Δφ/2) + + Math.cos(φ1) * Math.cos(φ2) * + Math.sin(Δλ/2) * Math.sin(Δλ/2); + var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); + + return R * c; +} + +/** + * recordRoute handler. Gets a stream of points, and responds with statistics + * about the "trip": number of points, number of known features visited, total + * distance traveled, and total time spent. + * @param {Readable} call The request point stream. + * @param {function(Error, routeSummary)} callback The callback to pass the + * response to + */ +function recordRoute(call, callback) { + var point_count = 0; + var feature_count = 0; + var distance = 0; + var previous = null; + // Start a timer + var start_time = process.hrtime(); + call.on('data', function(point) { + point_count += 1; + if (checkFeature(point).name !== '') { + feature_count += 1; + } + /* For each point after the first, add the incremental distance from the + * previous point to the total distance value */ + if (previous != null) { + distance += getDistance(previous, point); + } + previous = point; + }); + call.on('end', function() { + callback(null, { + point_count: point_count, + feature_count: feature_count, + // Cast the distance to an integer + distance: distance|0, + // End the timer + elapsed_time: process.hrtime(start_time)[0] + }); + }); +} + +var route_notes = {}; + +/** + * Turn the point into a dictionary key. + * @param {point} point The point to use + * @return {string} The key for an object + */ +function pointKey(point) { + return point.latitude + ' ' + point.longitude; +} + +/** + * routeChat handler. Receives a stream of message/location pairs, and responds + * with a stream of all previous messages at each of those locations. + * @param {Duplex} call The stream for incoming and outgoing messages + */ +function routeChat(call) { + call.on('data', function(note) { + var key = pointKey(note.location); + /* For each note sent, respond with all previous notes that correspond to + * the same point */ + if (route_notes.hasOwnProperty(key)) { + _.each(route_notes[key], function(note) { + call.write(note); + }); + } else { + route_notes[key] = []; + } + // Then add the new note to the list + route_notes[key].push(JSON.parse(JSON.stringify(note))); + }); + call.on('end', function() { + call.end(); + }); +} + +/** + * Get a new server with the handler functions in this file bound to the methods + * it serves. + * @return {Server} The new server object + */ +function getServer() { + return new Server({ + 'examples.RouteGuide' : { + getFeature: getFeature, + listFeatures: listFeatures, + recordRoute: recordRoute, + routeChat: routeChat + } + }); +} + +if (require.main === module) { + // If this is run as a script, start a server on an unused port + var routeServer = getServer(); + routeServer.bind('0.0.0.0:50051'); + var argv = parseArgs(process.argv, { + string: 'db_path' + }); + fs.readFile(path.resolve(argv.db_path), function(err, data) { + if (err) throw err; + feature_list = JSON.parse(data); + routeServer.listen(); + }); +} + +exports.getServer = getServer; |