proto

Documentation

Index

• func FixFieldMasks(jsonMessage []byte, messageType reflect.Type) ([]byte, error)
• func PageQuery(c context.Context, lim int32, tok string, rsp PagedResponse, ...) error
• func ParseMultilineStrings(text string) (string, error)
• func UnmarshalTextML(s string, pb proto.Message) error
• type PagedResponse

Functions

func FixFieldMasks

func FixFieldMasks(jsonMessage []byte, messageType reflect.Type) ([]byte, error)

FixFieldMasks reads FieldMask fields from a JSON-encoded message, parses them as a string according to https://github.com/protocolbuffers/protobuf/blob/ec1a70913e5793a7d0a7b5fbf7e0e4f75409dd41/src/google/protobuf/field_mask.proto#L180 and converts them to a JSON object that Golang Protobuf library understands. It is a workaround for https://github.com/golang/protobuf/issues/745.

messageType must be a struct, not a struct pointer.

func PageQuery

func PageQuery(c context.Context, lim int32, tok string, rsp PagedResponse, q *datastore.Query, cb interface{}) error

PageQuery executes a query to fetch the given page of results, invoking a callback function for each key or entity returned by the query. If the page isn't the last of the query, the given response will have its next page token set appropriately.

A non-positive limit means to fetch all results starting at the given page token in a single page. An empty page token means to start at the first page.

The callback must be a function of one argument, the type of which is either *datastore.Key (implies keys-only query) or a pointer to a struct to decode the returned entity into. The callback should return an error, which if not nil halts the query, and if the error is not datastore.Stop, causes this function to return an error as well. See datastore.Run for more information. No maximum page size is imposed, use datastore.Stop to enforce one.

func ParseMultilineStrings

func ParseMultilineStrings(text string) (string, error)

ParseMultilineStrings looks for bash-style heredocs and replaces them with single-line text-proto-escaped strings.

This looks line by line for /<<\s*([_a-zA-Z]+)\s*$/. If this is found, the scanner then looks until it finds /^\s*\1\s*$/. Every line between these is joined like "\n".join(lines), and then printed back as an escaped proto string. The scanner then loops back to its initial state.

Not that nothing special needs to be done for e.g.

some_key: "string with << angles"

Such a line would be left alone, because the trailing quote (which is mandatory in text proto) cause the starting regex to not match.

For convenience, the inner lines will be treated with the equivalent of python's `textwrap.dedent`; any common leading whitespace that occurs on every line will be removed. Although both tabs and spaces count as whitespace, they are not equivalent (i.e. only exactly-matching whitespace prefixes count)

The only error this may return is if there's an open heredoc without a matching close marker.

Example:

  this: <<EOF
	   would
	   turn \ninto
      a "single"
    line
  EOF

Turns into the same as:

this: "would\nturn \\ninto\n  a \"single\"\nline"

func UnmarshalTextML

func UnmarshalTextML(s string, pb proto.Message) error

UnmarshalTextML behaves the same as proto.UnmarshalText, except that it allows for multiline strings in the manner of ParseMultilineStrings.

Types

type PagedResponse

type PagedResponse interface {
	proto.Message
	// GetNextPageToken returns a token to use to fetch the next page of results.
	GetNextPageToken() string
}

PagedResponse is an interface implemented by ListResponses which support page tokens.