Improve ./scripts/dump to use custom .proto

[springmeyer]

It is possible to use a custom .proto when generating new fixtures, like fixture 11 does:

mvt-fixtures/src/011.js

Line 116 in d015ae5

proto: proto_string

.

It is also possible to later reference this custom .proto since it is embedded into the info.json like

mvt-fixtures/fixtures/011/info.json

Line 9 in d015ae5

"proto": "\npackage vector_tile;\n\noption optimize_for = LITE_RUNTIME;\n\nmessage Tile {\n\n // GeomType is described in section 4.3.4 of the specification\n enum GeomType {\n UNKNOWN = 0;\n POINT = 1;\n LINESTRING = 2;\n POLYGON = 3;\n }\n // THIS IS NEW\n message NewMessageInValue {\n required string name = 1;\n }\n\n // Variant type encoding\n // The use of values is described in section 4.1 of the specification\n message Value {\n // Exactly one of these values must be present in a valid message\n optional string string_value = 1;\n optional float float_value = 2;\n optional double double_value = 3;\n optional int64 int_value = 4;\n optional uint64 uint_value = 5;\n optional sint64 sint_value = 6;\n optional bool bool_value = 7;\n optional NewMessageInValue custom_value = 8; // THIS IS NEW\n }\n\n // Features are described in section 4.2 of the specification\n message Feature {\n optional uint64 id = 1 [ default = 0 ];\n\n // Tags of this feature are encoded as repeated pairs of\n // integers.\n // A detailed description of tags is located in sections\n // 4.2 and 4.4 of the specification\n repeated uint32 tags = 2 [ packed = true ];\n\n // The type of geometry stored in this feature.\n optional GeomType type = 3 [ default = UNKNOWN ];\n\n // Contains a stream of commands and parameters (vertices).\n // A detailed description on geometry encoding is located in\n // section 4.3 of the specification.\n repeated uint32 geometry = 4 [ packed = true ];\n }\n\n // Layers are described in section 4.1 of the specification\n message Layer {\n // Any compliant implementation must first read the version\n // number encoded in this message and choose the correct\n // implementation for this version number before proceeding to\n // decode other parts of this message.\n required uint32 version = 15 [ default = 1 ];\n\n required string name = 1;\n\n // The actual features in this tile.\n repeated Feature features = 2;\n\n // Dictionary encoding for keys\n repeated string keys = 3;\n\n // Dictionary encoding for values\n repeated Value values = 4;\n\n // Although this is an \"optional\" field it is required by the specification.\n // See https://github.com/mapbox/vector-tile-spec/issues/47\n optional uint32 extent = 5 [ default = 4096 ];\n\n extensions 16 to max;\n }\n\n repeated Layer layers = 3;\n\n extensions 16 to 8191;\n}\n"

.

But the ./scripts/dump currently hardcodes to .proto used to decode the tile at

mvt-fixtures/scripts/dump

Line 23 in d015ae5

vector-tile-spec/2.1/vector_tile.proto \

. This hardcoding means that if a custom .proto where to add a new field, the scripts/dump would not be able to display the correct field name.

So, to improve this we should enhance scripts/dump to find a way to read the .proto via the info.json. Perhaps the ./scripts/dump could be changed to simply:

• accept an argument of a number (to denote a fixture id) rather than the path to the tile.mvt
• then it would find both the tile.mvt and the info.json for a given fixture and dump the data using the correct, potentially custom, .proto string.