-
Notifications
You must be signed in to change notification settings - Fork 1.1k
/
HttpMain.java
273 lines (234 loc) · 10.6 KB
/
HttpMain.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
package example.http;
import graphql.ExecutionInput;
import graphql.ExecutionResult;
import graphql.GraphQL;
import graphql.StarWarsData;
import graphql.execution.instrumentation.tracing.TracingInstrumentation;
import graphql.schema.DataFetcher;
import graphql.schema.GraphQLObjectType;
import graphql.schema.GraphQLSchema;
import graphql.schema.TypeResolver;
import graphql.schema.idl.RuntimeWiring;
import graphql.schema.idl.SchemaGenerator;
import graphql.schema.idl.SchemaParser;
import graphql.schema.idl.TypeDefinitionRegistry;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.dataloader.BatchLoader;
import org.dataloader.DataLoader;
import org.dataloader.DataLoaderFactory;
import org.dataloader.DataLoaderRegistry;
import org.eclipse.jetty.server.Handler;
import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.handler.AbstractHandler;
import org.eclipse.jetty.server.handler.HandlerList;
import org.eclipse.jetty.server.handler.ResourceHandler;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CompletableFuture;
import static graphql.ExecutionInput.newExecutionInput;
import static graphql.schema.idl.TypeRuntimeWiring.newTypeWiring;
/**
* A very simple example of serving a graphql schema over http.
* <p>
* More info can be found here : <a href="https://graphql.org/learn/serving-over-http/">https://graphql.org/learn/serving-over-http/</a>
*/
@SuppressWarnings("unchecked")
public class HttpMain extends AbstractHandler {
static final int PORT = 8080;
static GraphQLSchema starWarsSchema = null;
public static void main(String[] args) throws Exception {
//
// This example uses Jetty as an embedded HTTP server
Server server = new Server(PORT);
//
// In Jetty, handlers are how your get called backed on a request
HttpMain main_handler = new HttpMain();
ResourceHandler resource_handler = new ResourceHandler();
resource_handler.setDirectoriesListed(false);
resource_handler.setWelcomeFiles(new String[]{"index.html"});
resource_handler.setResourceBase("./src/test/resources/httpmain");
HandlerList handlers = new HandlerList();
handlers.setHandlers(new Handler[]{resource_handler, main_handler});
server.setHandler(handlers);
server.start();
server.join();
}
@Override
public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
boolean handled = false;
if ("/graphql".equals(target)) {
handleStarWars(request, response);
handled = true;
} else if (target.startsWith("/executionresult")) {
new ExecutionResultJSONTesting(target, response);
handled = true;
}
if (handled) {
baseRequest.setHandled(true);
}
}
private void handleStarWars(HttpServletRequest httpRequest, HttpServletResponse httpResponse) throws IOException {
//
// this builds out the parameters we need like the graphql query from the http request
QueryParameters parameters = QueryParameters.from(httpRequest);
if (parameters.getQuery() == null) {
//
// how to handle nonsensical requests is up to your application
httpResponse.setStatus(400);
return;
}
//
// This example uses the DataLoader technique to ensure that the most efficient
// loading of data (in this case StarWars characters) happens.
//
DataLoaderRegistry dataLoaderRegistry = buildDataLoaderRegistry();
ExecutionInput.Builder executionInput = newExecutionInput()
.query(parameters.getQuery())
.operationName(parameters.getOperationName())
.variables(parameters.getVariables())
.dataLoaderRegistry(dataLoaderRegistry);
//
// the context object is something that means something to down stream code. It is instructions
// from yourself to your other code such as DataFetchers. The engine passes this on unchanged and
// makes it available to inner code
//
// the graphql guidance says :
//
// - GraphQL should be placed after all authentication middleware, so that you
// - have access to the same session and user information you would in your
// - HTTP endpoint handlers.
//
Map<String, Object> context = new HashMap<>();
context.put("YouAppSecurityClearanceLevel", "CodeRed");
context.put("YouAppExecutingUser", "Dr Nefarious");
executionInput.graphQLContext(context);
//
// you need a schema in order to execute queries
GraphQLSchema schema = buildStarWarsSchema();
// finally you build a runtime graphql object and execute the query
GraphQL graphQL = GraphQL
.newGraphQL(schema)
.instrumentation(new TracingInstrumentation())
.build();
ExecutionResult executionResult = graphQL.execute(executionInput);
returnAsJson(httpResponse, executionResult);
}
private void returnAsJson(HttpServletResponse response, ExecutionResult executionResult) throws IOException {
sendNormalResponse(response, executionResult);
}
private void sendNormalResponse(HttpServletResponse response, ExecutionResult executionResult) throws IOException {
response.setContentType("application/json");
response.setStatus(HttpServletResponse.SC_OK);
JsonKit.toJson(response, executionResult.toSpecification());
}
private DataLoaderRegistry buildDataLoaderRegistry() {
BatchLoader<String, Object> friendsBatchLoader = keys ->
//
// we are using multi threading here. Imagine if loadCharactersViaHTTP was
// actually a HTTP call - its not be it could be done asynchronously as
// a batch API call
//
CompletableFuture.supplyAsync(() ->
loadCharactersViaHTTP(keys));
DataLoader<String, Object> friendsDataLoader = DataLoaderFactory.newDataLoader(friendsBatchLoader);
DataLoaderRegistry dataLoaderRegistry = new DataLoaderRegistry();
//
// we make sure our dataloader is in the registry
dataLoaderRegistry.register("friends", friendsDataLoader);
return dataLoaderRegistry;
}
private GraphQLSchema buildStarWarsSchema() {
//
// using lazy loading here ensure we can debug the schema generation
// and potentially get "wired" components that cant be accessed
// statically.
//
// A full application would use a dependency injection framework (like Spring)
// to manage that lifecycle.
//
if (starWarsSchema == null) {
//
//
// the fetcher of friends uses java-dataloader to make the circular friends fetching
// more efficient by batching and caching the calls to load Character friends
//
DataFetcher friendsFetcher = environment -> {
DataLoader friendsDataLoader = environment.getDataLoader("friends");
List<String> friendIds = asMapGet(environment.getSource(), "friends");
return friendsDataLoader.loadMany(friendIds);
};
//
// reads a file that provides the schema types
//
Reader streamReader = loadSchemaFile("starWarsSchemaAnnotated.graphqls");
TypeDefinitionRegistry typeRegistry = new SchemaParser().parse(streamReader);
//
// the runtime wiring is used to provide the code that backs the
// logical schema
//
TypeResolver characterTypeResolver = env -> {
Map<String, Object> obj = env.getObject();
String id = (String) obj.get("id");
GraphQLSchema schema = env.getSchema();
if (StarWarsData.isHuman(id)) {
return (GraphQLObjectType) schema.getType("Human");
} else {
return (GraphQLObjectType) schema.getType("Droid");
}
};
RuntimeWiring wiring = RuntimeWiring.newRuntimeWiring()
.type(newTypeWiring("Query")
.dataFetcher("hero", StarWarsData.getHeroDataFetcher())
.dataFetcher("human", StarWarsData.getHumanDataFetcher())
.dataFetcher("droid", StarWarsData.getDroidDataFetcher())
)
.type(newTypeWiring("Human")
.dataFetcher("friends", friendsFetcher)
)
.type(newTypeWiring("Droid")
.dataFetcher("friends", friendsFetcher)
)
.type(newTypeWiring("Character")
.typeResolver(characterTypeResolver)
)
.type(newTypeWiring("Episode")
.enumValues(StarWarsData.getEpisodeResolver())
)
.build();
// finally combine the logical schema with the physical runtime
starWarsSchema = new SchemaGenerator().makeExecutableSchema(typeRegistry, wiring);
}
return starWarsSchema;
}
private List<Object> loadCharactersViaHTTP(List<String> keys) {
List<Object> values = new ArrayList<>();
for (String key : keys) {
Object character = StarWarsData.getCharacter(key);
values.add(character);
}
return values;
}
@SuppressWarnings("SameParameterValue")
private Reader loadSchemaFile(String name) {
InputStream stream = getClass().getClassLoader().getResourceAsStream(name);
return new InputStreamReader(stream, Charset.defaultCharset());
}
// Lots of the data happens to be maps of objects and this allows us to get back into type safety land
// with less boilerplate and casts
//
@SuppressWarnings("TypeParameterUnusedInFormals")
private <T> T asMapGet(Object mapObj, Object mapKey) {
Map<Object, ?> map = (Map<Object, ?>) mapObj;
return (T) map.get(mapKey);
}
}