mirror of
https://github.com/google/flatbuffers.git
synced 2026-06-10 15:16:28 +00:00
Move docs/ to docs-old/
This commit is contained in:
99
docs-old/source/GoUsage.md
Normal file
99
docs-old/source/GoUsage.md
Normal file
@@ -0,0 +1,99 @@
|
||||
Use in Go {#flatbuffers_guide_use_go}
|
||||
=========
|
||||
|
||||
## Before you get started
|
||||
|
||||
Before diving into the FlatBuffers usage in Go, it should be noted that
|
||||
the [Tutorial](@ref flatbuffers_guide_tutorial) page has a complete guide
|
||||
to general FlatBuffers usage in all of the supported languages (including Go).
|
||||
This page is designed to cover the nuances of FlatBuffers usage, specific to
|
||||
Go.
|
||||
|
||||
You should also have read the [Building](@ref flatbuffers_guide_building)
|
||||
documentation to build `flatc` and should be familiar with
|
||||
[Using the schema compiler](@ref flatbuffers_guide_using_schema_compiler) and
|
||||
[Writing a schema](@ref flatbuffers_guide_writing_schema).
|
||||
|
||||
## FlatBuffers Go library code location
|
||||
|
||||
The code for the FlatBuffers Go library can be found at
|
||||
`flatbuffers/go`. You can browse the library code on the [FlatBuffers
|
||||
GitHub page](https://github.com/google/flatbuffers/tree/master/go).
|
||||
|
||||
## Testing the FlatBuffers Go library
|
||||
|
||||
The code to test the Go library can be found at `flatbuffers/tests`.
|
||||
The test code itself is located in [go_test.go](https://github.com/google/
|
||||
flatbuffers/blob/master/tests/go_test.go).
|
||||
|
||||
To run the tests, use the [GoTest.sh](https://github.com/google/flatbuffers/
|
||||
blob/master/tests/GoTest.sh) shell script.
|
||||
|
||||
*Note: The shell script requires [Go](https://golang.org/doc/install) to
|
||||
be installed.*
|
||||
|
||||
## Using the FlatBuffers Go library
|
||||
|
||||
*Note: See [Tutorial](@ref flatbuffers_guide_tutorial) for a more in-depth
|
||||
example of how to use FlatBuffers in Go.*
|
||||
|
||||
FlatBuffers supports reading and writing binary FlatBuffers in Go.
|
||||
|
||||
To use FlatBuffers in your own code, first generate Go classes from your
|
||||
schema with the `--go` option to `flatc`. Then you can include both FlatBuffers
|
||||
and the generated code to read or write a FlatBuffer.
|
||||
|
||||
For example, here is how you would read a FlatBuffer binary file in Go: First,
|
||||
include the library and generated code. Then read a FlatBuffer binary file into
|
||||
a `[]byte`, which you pass to the `GetRootAsMonster` function:
|
||||
|
||||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~{.go}
|
||||
import (
|
||||
example "MyGame/Example"
|
||||
flatbuffers "github.com/google/flatbuffers/go"
|
||||
|
||||
"os"
|
||||
)
|
||||
|
||||
buf, err := os.ReadFile("monster.dat")
|
||||
// handle err
|
||||
monster := example.GetRootAsMonster(buf, 0)
|
||||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
||||
|
||||
Now you can access values like this:
|
||||
|
||||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~{.go}
|
||||
hp := monster.Hp()
|
||||
pos := monster.Pos(nil)
|
||||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
||||
|
||||
|
||||
In some cases it's necessary to modify values in an existing FlatBuffer in place (without creating a copy). For this reason, scalar fields of a Flatbuffer table or struct can be mutated.
|
||||
|
||||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~{.go}
|
||||
monster := example.GetRootAsMonster(buf, 0)
|
||||
|
||||
// Set table field.
|
||||
if ok := monster.MutateHp(10); !ok {
|
||||
panic("failed to mutate Hp")
|
||||
}
|
||||
|
||||
// Set struct field.
|
||||
monster.Pos().MutateZ(4)
|
||||
|
||||
// This mutation will fail because the mana field is not available in
|
||||
// the buffer. It should be set when creating the buffer.
|
||||
if ok := monster.MutateMana(20); !ok {
|
||||
panic("failed to mutate Hp")
|
||||
}
|
||||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
||||
|
||||
The term `mutate` is used instead of `set` to indicate that this is a special use case. All mutate functions return a boolean value which is false if the field we're trying to mutate is not available in the buffer.
|
||||
|
||||
## Text Parsing
|
||||
|
||||
There currently is no support for parsing text (Schema's and JSON) directly
|
||||
from Go, though you could use the C++ parser through cgo. Please see the
|
||||
C++ documentation for more on text parsing.
|
||||
|
||||
<br>
|
||||
Reference in New Issue
Block a user