MessagePack

Documentation Index

Fetch the complete documentation index at: https://docs.go-mizu.dev/llms.txt

Use this file to discover all available pages before exploring further.

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Overview

• Binary serialization
• Reduced payload size
• Faster parsing

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Installation

import "github.com/go-mizu/mizu/middlewares/msgpack"

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Quick Start

app := mizu.New()

app.Use(msgpack.New())

app.Get("/data", func(c *mizu.Ctx) error {
    // Auto-negotiates based on Accept header
    return c.Negotiate(200, data)
})

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Examples

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Enable MessagePack

app.Use(msgpack.New())

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Explicit MessagePack Response

app.Get("/data", func(c *mizu.Ctx) error {
    return msgpack.Send(c, 200, data)
})

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Parse MessagePack Request

app.Post("/data", func(c *mizu.Ctx) error {
    var data MyStruct
    if err := msgpack.Bind(c, &data); err != nil {
        return err
    }
    return c.JSON(200, data)
})

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Content Negotiation

app.Use(msgpack.New())

app.Get("/data", func(c *mizu.Ctx) error {
    // Returns MessagePack if Accept: application/msgpack
    // Returns JSON if Accept: application/json
    return c.Negotiate(200, data)
})

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API Reference

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Functions

// New creates MessagePack middleware
func New() mizu.Middleware

// Send sends MessagePack response
func Send(c *mizu.Ctx, status int, data any) error

// Bind parses MessagePack request body
func Bind(c *mizu.Ctx, v any) error

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Content Types

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Technical Details

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Architecture

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Middleware Handler

• Intercepts requests with MessagePack content types
• Stores raw request body in context for later parsing
• Supports configurable content types (default: application/msgpack, application/x-msgpack)

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Encoder

• Implements MessagePack binary format specification
• Uses fixed-size optimizations for common value ranges
• Supports fixint, int8/16/32/64, uint8/16/32/64 encoding
• Handles fixstr, str8/16/32 for strings with automatic size selection
• Encodes binary data with bin8/16/32 formats
• Supports fixarray, array16/32 and fixmap, map16/32 structures

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Decoder

• Parses MessagePack binary format to Go values
• Returns generic any types (string, int64, uint64, float32/64, []any, map[string]any)
• Validates buffer boundaries to prevent out-of-bounds access
• Handles all MessagePack type codes including fixint, negative fixint, and type-specific codes

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Type Mappings

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Error Handling

• ErrUnsupportedType: Returned when attempting to encode unsupported Go types
• ErrInvalidFormat: Returned when decoding encounters invalid MessagePack data
• ErrBufferTooSmall: Returned when the input buffer is insufficient for the declared data

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Context Storage

• Multiple reads of the request body
• Access via the Body() helper function
• Preservation of the original request body for middleware chain

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Best Practices

• Use for internal APIs
• Fall back to JSON for browsers
• Consider client library support
• Benchmark for your use case

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Testing

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Test Coverage

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Related Middlewares

• contenttype - Content-Type validation
• compress - Response compression
• xml - XML handling