PROTOBUF text format analysis map

map aToB

aToB {
 123 : "foo"
}

aToB {# (this example has a bug)
 key: 123
 value : "foo"
 key: 876 # WRONG!
 value: "bar" # NOPE!
}

libprotobuf ERROR: Non-repeated field "key" is specified multiple times.

aToB {
 key: 123
 value: "foo"
 }
aToB {
 key: 876 
 value: "bar" 
}

syntax = "proto3";
package myproject.testing;

message UserRecord {
 string handle = 10;
 bool paid_membership = 20;
}

message UserCollection {
 string descr iption = 20;
 // HERE IS THE PROTOBUF MAP-TYPE FIELD:
 map users = 10;
}

message TestData {< br /> UserCollection user_collection = 10;
}

user_collection {
 description = "my default users"
 users {
 key: "user_1234"
 value {
 handle: "winniepoo"
 paid_membership: true
 }
 }
 users {
 key: "user_9b27"
 value {
 handle: "smokeybear"
 }
 }
 }

myproject::testing::UserRecord user_1;
user_1.set_handle("winniepoo" );
user_1.set_paid_membership(true);
myproject::testing::UserRecord user_2;
user_2.set_handle("smokeybear");
user_2.set_paid_membership(false); 

using pair_type =
 google::protobuf::MapPair;

myproject::testing: :TestData data;
d ata.mutable_user_collection()->mutable_users()->insert(
 pair_type(std::string("user_1234"), user_1));
data.mutable_user_collection()->mutable_users()-> insert(
 pair_type(std::string("user_9b27"), user_2));

This answer clearly shows some examples of raw text parsing, But there is no example of a map.

If a prototype has:

map aToB

I Guess it is like this:

aToB {
 123: "foo"
}

But it doesn’t work. Anyone Know the exact syntax?

I initially tried to infer from the earlier answer, which led me astray because I mistakenly thought that multiple k/v pairs looked like this: < p>

aToB {# (this example has a bug)
 key: 123
 value: "foo"
 key: 876 # WRONG!
 value: "bar" # NOPE!
}

This resulted in the following error:

libprotobuf ERROR: Non -repeated field "key" is specified multiple times.

Syntax for multiple key-value pairs:

(Note: I am using “proto3” of the protocol buffer language Version)

aToB {
 key: 123
 value: "foo"
}
aToB {
 key : 876 
 value: "bar" 
}

It makes more sense to repeat the pattern of map variable names after re-reading this relevant portion of the proto3 Map documentation, which explains the map equivalent Define your own “right” message type, and then mark it as “repeat”.

A more complete example:

Prototype definition:

syntax = "proto3";
package myproject.testing;

message UserRecord {
 string handle = 10;
 bool paid_membership = 20 ;
}

message UserCollection {
 string description = 20;
 // HERE IS THE PROTOBUF MAP-TYPE FIELD:
 map users = 10;
}

message TestData {
 UserCollection user_collection = 10;
}

In the configuration file Text format (“pbtxt”):

user_collection {
 description = "my default users"
 users {
 key: "user_1234 "
 value {
 handle: "winniepoo"
 paid_membership: true
 }
 }
 users {
 key: "user_9b27"
 value {
 handle: "smokeybear"
 }
 }
}

C will programmatically generate message content

myproject::testing::UserRecord user_1;
user_1.set_handle("winniepoo");
user_1.set_paid_membership(true);
myproject::testing:: UserRecord user_2;
user_2.set_handle("smokeybear");
user_2.set_paid_membership(false);

using pair_type =
 google::protobuf::MapPair< std::string, myproject::testing::UserRecord>;

myproject::testing::TestData data;
data.mutable_user_collection()->mutable_users()->insert(< br /> pair_ty pe(std::string("user_1234"), user_1));
data.mutable_user_collection()->mutable_users()->insert(
 pair_type(std::string("user_9b27"), user_2));