Doing reflection on a map is a little bit tricky, but the way to do it is to treat it as a repeated field since that is how it is actually represented on the wire. A map is a stored as a repeated message field, where in each message the key is field 1 and the value is field 2.
On Mon, Jun 5, 2017 at 1:37 AM, Qian Zhang <[email protected]> wrote: > Hi Adam, > > We are using picojson <https://github.com/kazuho/picojson> to parse the > JSON file. > > After more debugging, I think I have found the root cause: In the code > here > <https://github.com/apache/mesos/blob/1.2.0/3rdparty/stout/include/stout/protobuf.hpp#L575>, > we are trying to find a field by the key of an entry in a map, obviously it > will fail since the key of any map entries is not in the protobuf message > definition (the .proto file), and to avoid finding field by a map entry's > key, in this method > <https://github.com/apache/mesos/blob/1.2.0/3rdparty/stout/include/stout/protobuf.hpp#L387:L407>, > we need to check if "field->is_map()" is true which is currently missed, if > the field is a map, then we should use the reflection to construct a map > message, however I do not find a method in protobuf to do that, I find a > lot of "Addxxx()" methods (e.g., "AddString()", "AddInt64()", etc.), but > not a method for adding a map. There is a method > "InsertOrLookupMapValue()", but that is a private method which I can not > call in my code. > > So can you please suggest how to add a map message? Thanks! > > > Regards, > Qian Zhang > > On Sat, Jun 3, 2017 at 1:02 AM, Adam Cozzette <[email protected]> > wrote: > >> It looks to me like your JSON syntax is right. Could you post the C++ >> code you are using to parse the JSON file? >> >> On Fri, Jun 2, 2017 at 1:16 AM, Qian Zhang <[email protected]> wrote: >> >>> Hi, >>> >>> I have a C++ project in which there is a .proto file, and in that file, >>> there is protobuf message which has a map field: >>> "map<string, string> annotations = 5;" >>> >>> And the JSON file to be parsed with that .proto file has the following >>> content: >>> "annotations": { >>> "com.example.key1": "value1", >>> "com.example.key2": "value2" >>> } >>> >>> The .proto file is in proto2 syntax (it has "syntax = "proto2";" at the >>> beginning) and I am using protobuf-3.3.0, the compilation succeed, but I >>> found the annotation map always has only one entry, and both the entry's >>> key and value are "" which is obviously not correct. >>> >>> Any suggestions? >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Protocol Buffers" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> To post to this group, send email to [email protected]. >>> Visit this group at https://groups.google.com/group/protobuf. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> > -- You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/protobuf. For more options, visit https://groups.google.com/d/optout.
