1MONGOC_CLIENT_READ_COMMAND_WITH_MOoPnTgSo(D3B)CMODNrGiOvCe_rCLIENT_READ_COMMAND_WITH_OPTS(3)
2
6 mongoc_client_read_command_with_opts - mongoc_client_read_com‐
7 mand_with_opts()
8
10 bool
11 mongoc_client_read_command_with_opts (mongoc_client_t *client,
12 const char *db_name,
13 const bson_t *command,
14 const mongoc_read_prefs_t *read_prefs,
15 const bson_t *opts,
16 bson_t *reply,
17 bson_error_t *error);
18 Execute a command on the server, applying logic that is specific to
20 commands that read, and taking the MongoDB server version into account.
21 To send a raw command to the server without any of this logic, use mon‐
22 goc_client_command_simple.
23 Use this function for commands that read such as "count" or "distinct".
25 Read preferences, read concern, and collation can be overridden by var‐
27 ious sources. In a transaction, read concern and write concern are pro‐
28 hibited in opts and the read preference must be primary or NULL. The
29 highest-priority sources for these options are listed first in the fol‐
30 lowing table. No write concern is applied.
31 ┌─────────────────┬──────────────┬───────────┐
33 │Read Preferences │ Read Concern │ Collation │
34 ├─────────────────┼──────────────┼───────────┤
35 │read_prefs │ opts │ opts │
36 ├─────────────────┼──────────────┼───────────┤
37 │Transaction │ Transaction │ │
38 ├─────────────────┼──────────────┼───────────┤
39 │client │ │ │
40 └─────────────────┴──────────────┴───────────┘
41 See the example for transactions and for the "distinct" command with
43 opts.
44 reply is always initialized, and must be freed with bson_destroy().
46
48 · client: A mongoc_client_t.
49 · db_name: The name of the database to run the command on.
51 · command: A bson_t containing the command specification.
53 · read_prefs: An optional mongoc_read_prefs_t.
55 · opts: A bson_t containing additional options.
57 · reply: A location for the resulting document.
59 · error: An optional location for a bson_error_t or NULL.
61 opts may be NULL or a BSON document with additional command options:
63 · readConcern: Construct a mongoc_read_concern_t and use mon‐
65 goc_read_concern_append to add the read concern to opts. See the
66 example code for mongoc_client_read_command_with_opts. Read concern
67 requires MongoDB 3.2 or later, otherwise an error is returned.
68 · sessionId: First, construct a mongoc_client_session_t with mon‐
70 goc_client_start_session. You can begin a transaction with mon‐
71 goc_client_session_start_transaction, optionally with a mongoc_trans‐
72 action_opt_t that overrides the options inherited from client, and
73 use mongoc_client_session_append to add the session to opts. See the
74 example code for mongoc_client_session_t.
75 · collation: Configure textual comparisons. See Setting Collation
77 Order, and the MongoDB Manual entry on Collation. Collation requires
78 MongoDB 3.2 or later, otherwise an error is returned.
79 · serverId: To target a specific server, include an int32 "serverId"
81 field. Obtain the id by calling mongoc_client_select_server, then
82 mongoc_server_description_id on its return value.
83 Consult the MongoDB Manual entry on Database Commands for each com‐
85 mand's arguments.
86
88 Errors are propagated via the error parameter.
89
91 Returns true if successful. Returns false and sets error if there are
92 invalid arguments or a server or network error.
93
95 example-command-with-opts.c.INDENT 0.0
96 /*
98 Demonstrates how to prepare options for mongoc_client_read_command_with_opts and
100 mongoc_client_write_command_with_opts. First it calls "cloneCollectionAsCapped"
101 command with "writeConcern" option, then "distinct" command with "collation" and
102 "readConcern" options,
103 Start a MongoDB 3.4 replica set with --enableMajorityReadConcern and insert two
105 documents:
106 $ mongo
108 MongoDB Enterprise replset:PRIMARY> db.my_collection.insert({x: 1, y: "One"})
109 WriteResult({ "nInserted" : 1 })
110 MongoDB Enterprise replset:PRIMARY> db.my_collection.insert({x: 2, y: "Two"})
111 WriteResult({ "nInserted" : 1 })
112 Build and run the example:
114 gcc example-command-with-opts.c -o example-command-with-opts $(pkg-config
116 --cflags --libs libmongoc-1.0)
117 ./example-command-with-opts [CONNECTION_STRING]
118 cloneCollectionAsCapped: { "ok" : 1 }
119 distinct: { "values" : [ 1, 2 ], "ok" : 1 }
120 */
122 #include <mongoc/mongoc.h>
124 #include <stdio.h>
125 #include <stdlib.h>
126 int
128 main (int argc, char *argv[])
129 {
130 mongoc_client_t *client;
131 const char *uri_string = "mongodb://127.0.0.1/?appname=client-example";
132 mongoc_uri_t *uri;
133 bson_t *cmd;
134 bson_t *opts;
135 mongoc_write_concern_t *write_concern;
136 mongoc_read_prefs_t *read_prefs;
137 mongoc_read_concern_t *read_concern;
138 bson_t reply;
139 bson_error_t error;
140 char *json;
141 mongoc_init ();
143 if (argc > 1) {
145 uri_string = argv[1];
146 }
147 uri = mongoc_uri_new_with_error (uri_string, &error);
149 if (!uri) {
150 fprintf (stderr,
151 "failed to parse URI: %s\n"
152 "error message: %s\n",
153 uri_string,
154 error.message);
155 return EXIT_FAILURE;
156 }
157 client = mongoc_client_new_from_uri (uri);
159 if (!client) {
160 return EXIT_FAILURE;
161 }
162 mongoc_client_set_error_api (client, 2);
164 cmd = BCON_NEW ("cloneCollectionAsCapped",
166 BCON_UTF8 ("my_collection"),
167 "toCollection",
168 BCON_UTF8 ("my_capped_collection"),
169 "size",
170 BCON_INT64 (1024 * 1024));
171 /* include write concern "majority" in command options */
173 write_concern = mongoc_write_concern_new ();
174 mongoc_write_concern_set_wmajority (write_concern, 10000 /* wtimeoutMS */);
175 opts = bson_new ();
176 mongoc_write_concern_append (write_concern, opts);
177 if (mongoc_client_write_command_with_opts (
179 client, "test", cmd, opts, &reply, &error)) {
180 json = bson_as_canonical_extended_json (&reply, NULL);
181 printf ("cloneCollectionAsCapped: %s\n", json);
182 bson_free (json);
183 } else {
184 fprintf (stderr, "cloneCollectionAsCapped: %s\n", error.message);
185 }
186 bson_free (cmd);
188 bson_free (opts);
189 /* distinct values of "x" in "my_collection" where "y" sorts after "one" */
191 cmd = BCON_NEW ("distinct",
192 BCON_UTF8 ("my_collection"),
193 "key",
194 BCON_UTF8 ("x"),
195 "query",
196 "{",
197 "y",
198 "{",
199 "$gt",
200 BCON_UTF8 ("one"),
201 "}",
202 "}");
203 read_prefs = mongoc_read_prefs_new (MONGOC_READ_SECONDARY);
205 /* "One" normally sorts before "one"; make "One" sort after "one" */
207 opts = BCON_NEW ("collation",
208 "{",
209 "locale",
210 BCON_UTF8 ("en_US"),
211 "caseFirst",
212 BCON_UTF8 ("lower"),
213 "}");
214 /* add a read concern to "opts" */
216 read_concern = mongoc_read_concern_new ();
217 mongoc_read_concern_set_level (read_concern,
218 MONGOC_READ_CONCERN_LEVEL_MAJORITY);
219 mongoc_read_concern_append (read_concern, opts);
221 if (mongoc_client_read_command_with_opts (
223 client, "test", cmd, read_prefs, opts, &reply, &error)) {
224 json = bson_as_canonical_extended_json (&reply, NULL);
225 printf ("distinct: %s\n", json);
226 bson_free (json);
227 } else {
228 fprintf (stderr, "distinct: %s\n", error.message);
229 }
230 bson_destroy (cmd);
232 bson_destroy (opts);
233 bson_destroy (&reply);
234 mongoc_read_prefs_destroy (read_prefs);
235 mongoc_read_concern_destroy (read_concern);
236 mongoc_write_concern_destroy (write_concern);
237 mongoc_uri_destroy (uri);
238 mongoc_client_destroy (client);
239 mongoc_cleanup ();
241 return EXIT_SUCCESS;
243 }
244
247 MongoDB, Inc
248
250 2017-present, MongoDB, Inc
2511.13.1 Jan 24,MO2N0G1O9C_CLIENT_READ_COMMAND_WITH_OPTS(3)