What does the protobuf text format look like?

Question

Google Protocol Buffers can not only be serialized in binary format, also be serialized as text, known as textproto. However I can't easily find examples of such text; what would it look like?

Expected answer: an example covering all features allowed by the protobuf IDL/proto file including a sample protobuf packet in textual form.

Answer 1

Done myself:

test.proto

enum MyEnum {     Default = 0;     Variant1 = 1;     Variant100 = 100; }  message Test {     required string f1 = 1;     required int64 f2 = 2;     repeated uint64 fa = 3;     repeated int32 fb = 4;     repeated int32 fc = 5 [packed = true];     repeated Pair pairs = 6;     optional bytes bbbb = 7;      extensions 100 to max; }  message Pair {     required string key = 1;     optional string value = 2; }    extend Test {     optional bool gtt = 100;     optional double gtg = 101;     repeated MyEnum someEnum = 102; } 

example output:

f1: "dsfadsafsaf" f2: 234 fa: 2342134 fa: 2342135 fa: 2342136 fb: -2342134 fb: -2342135 fb: -2342136 fc: 4 fc: 7 fc: -12 fc: 4 fc: 7 fc: -3 fc: 4 fc: 7 fc: 0 pairs {   key: "sdfff"   value: "q\"qq\\q\n" } pairs {   key: "   sdfff2  \321\202\320\265\321\201\321\202 "   value: "q\tqq<>q2&\001\377" } bbbb: "\000\001\002\377\376\375" [gtt]: true [gtg]: 20.0855369 [someEnum]: Variant1 

the program:

#include <google/protobuf/text_format.h>  #include <stdio.h> #include "test.pb.h"  int main() {     Test t;     t.set_f1("dsfadsafsaf");     t.set_f2(234);     t.add_fa(2342134);     t.add_fa(2342135);     t.add_fa(2342136);     t.add_fb(-2342134);     t.add_fb(-2342135);     t.add_fb(-2342136);     t.add_fc(4);     t.add_fc(7);     t.add_fc(-12);     t.add_fc(4);     t.add_fc(7);     t.add_fc(-3);     t.add_fc(4);     t.add_fc(7);     t.add_fc(0);     t.set_bbbb("\x00\x01\x02\xff\xfe\xfd",6);      Pair *p1 = t.add_pairs(), *p2 = t.add_pairs();     p1->set_key("sdfff");     p1->set_value("q\"qq\\q\n");     p2->set_key("   sdfff2  тест ");     p2->set_value("q\tqq<>q2&\x01\xff");      t.SetExtension(gtt, true);     t.SetExtension(gtg, 20.0855369);     t.AddExtension(someEnum, Variant1);      std::string str;     google::protobuf::TextFormat::PrintToString(t, &str);     printf("%s", str.c_str());      return 0; } 

Binary protobuf of this sample (for completeness):

00000000  0a 0b 64 73 66 61 64 73  61 66 73 61 66 10 ea 01  |..dsfadsafsaf...| 00000010  18 f6 f9 8e 01 18 f7 f9  8e 01 18 f8 f9 8e 01 20  |............... | 00000020  8a 86 f1 fe ff ff ff ff  ff 01 20 89 86 f1 fe ff  |.......... .....| 00000030  ff ff ff ff 01 20 88 86  f1 fe ff ff ff ff ff 01  |..... ..........| 00000040  2a 1b 04 07 f4 ff ff ff  ff ff ff ff ff 01 04 07  |*...............| 00000050  fd ff ff ff ff ff ff ff  ff 01 04 07 00 32 10 0a  |.............2..| 00000060  05 73 64 66 66 66 12 07  71 22 71 71 5c 71 0a 32  |.sdfff..q"qq\q.2| 00000070  23 0a 14 20 20 20 73 64  66 66 66 32 20 20 d1 82  |#..   sdfff2  ..| 00000080  d0 b5 d1 81 d1 82 20 12  0b 71 09 71 71 3c 3e 71  |...... ..q.qq<>q| 00000090  32 26 01 ff 3a 06 00 01  02 ff fe fd a0 06 01 a9  |2&..:...........| 000000a0  06 ea 19 0c bf e5 15 34  40 b0 06 01              |.......4@...| 000000ac 

Note that it's the sample is not completely OK: libprotobuf ERROR google/protobuf/wire_format.cc:1059] Encountered string containing invalid UTF-8 data while parsing protocol buffer. Strings must contain only UTF-8; use the 'bytes' type for raw bytes.

Note that protoc tool also can decode messages to text, both with the proto file and without:

$ protoc --decode=Test test.proto < test.bin  [libprotobuf ERROR google/protobuf/wire_format.cc:1091] String field 'value' contains invalid UTF-8 data when parsing a protocol buffer. Use the 'bytes' type if you intend to send raw bytes.  f1: "dsfadsafsaf" f2: 234 fa: 2342134 fa: 2342135 fa: 2342136 fb: -2342134 fb: -2342135 fb: -2342136 fc: 4 fc: 7 fc: -12 fc: 4 fc: 7 fc: -3 fc: 4 fc: 7 fc: 0 pairs {   key: "sdfff"   value: "q\"qq\\q\n" } pairs {   key: "   sdfff2  \321\202\320\265\321\201\321\202 "   value: "q\tqq<>q2&\001\377" } bbbb: "\000\001\002\377\376\375" [gtt]: true [gtg]: 20.0855369 [someEnum]: Variant1 $ protoc --decode_raw  < test.bin  1: "dsfadsafsaf" 2: 234 3: 2342134 3: 2342135 3: 2342136 4: 18446744073707209482 4: 18446744073707209481 4: 18446744073707209480 5: "\004\007\364\377\377\377\377\377\377\377\377\001\004\007\375\377\377\377\377\377\377\377\377\001\004\007\000" 6 {   1: "sdfff"   2: "q\"qq\\q\n" } 6 {   1: "   sdfff2  \321\202\320\265\321\201\321\202 "   2: "q\tqq<>q2&\001\377" } 7: "\000\001\002\377\376\375" 100: 1 101: 0x403415e5bf0c19ea 102: 1