sse_parser

README

SSE Parser

This project provides a simple Server-Sent Events (SSE) parser written in Go. The parser is designed to handle streaming data and extract messages based on specific event and data patterns.

Features

• Incremental Parsing: Add data incrementally and parse messages as they become complete.
• Optional Completion Logic: Optionally define custom logic to determine when a message is complete.
• Error Handling: Skips invalid messages and logs errors.

Installation

To use this parser in your project, you need to have Go installed. Then, you can import the package:

go get github.com/GiGurra/sse-parser

Usage

Creating a Parser

You can create a new parser with or without a completion function:

import "github.com/GiGurra/sse-parser"

// Without a completion function
parser := sse_parser.NewParser(nil)

// With a completion function (optional)
parser := sse_parser.NewParser(func (data string) bool {
return strings.HasSuffix(data, "[END]")
})

Adding Data

You can add data to the parser incrementally:

messages := parser.Add("event:message\n" +
"data:hello\n\n" +
"event:message\n" +
"data:world")

Finishing Parsing

To finalize parsing and get any remaining messages:

finalMessages := parser.Finish()

Example

package main

import (
	"fmt"
	"github.com/GiGurra/sse-parser"
)

func main() {
	// Create a parser without a completion function
	parser := sse_parser.NewParser(nil)

	data := "event:message\n" +
		"data:hello\n\n" +
		"event:message\n" +
		"data:world"

	messages := parser.Add(data)
	messages = append(messages, parser.Finish()...)

	for _, msg := range messages {
		fmt.Printf("Event: %s, Data: %s\n", msg.Event, msg.Data)
	}
}

Streaming data

You can use a Parser to convert an io.Reader into a <-chan Message:

package main

import (
	"fmt"
	"github.com/GiGurra/sse-parser"
	"strings"
)

func main() {
	// Create a parser without a completion function
	parser := sse_parser.NewParser(nil)

	data := "event:message\n" +
		"data:hello\n\n" +
		"event:message\n" +
		"data:world"

	reader := strings.NewReader(data)
	bufSize := 100
	messages := parser.Stream(reader, bufSize)

	for msg := range messages {
		fmt.Printf("Event: %s, Data: %s\n", msg.Event, msg.Data)
	}
}

Behavior

• If no completion function is provided, the parser will consider a message complete when it encounters a double newline (\n\n).
• If a completion function is provided, it will be used to determine when a message's data is complete. WARNING: \n\n still indicates a hard separation between messages, so the completion function is only really necessary to handle cases where we have received the full data but not the \n\n yet.

Testing

The project includes a set of tests to verify the parser's functionality. You can run the tests using:

go test

License

This project is licensed under the MIT License. See the LICENSE file for details.

Contributing

Contributions are welcome! Please open an issue or submit a pull request for any improvements or bug fixes.

Future improvements

• The completion should be able to override the default behavior of considering a message complete when encountering a double newline.

---

Feel free to reach out if you have any questions or need further assistance. Happy coding!

Documentation

Index

• type Message
• type Parser
  • func NewParser(completeFn func(dataBytes string) bool) *Parser
  • func (p *Parser) Add(data string) []Message
  • func (p *Parser) Finish() []Message
  • func (p *Parser) Reset()
  • func (p *Parser) Stream(reader io.Reader, msgBufSize int) <-chan Message
• type Writer
  • func (w *Writer) Finish()
  • func (w *Writer) Write(p []byte) (n int, err error)

Types

type Message

type Message struct {
	Event string
	Data  string
}

type Parser

type Parser struct {
	// contains filtered or unexported fields
}

func NewParser

func NewParser(completeFn func(dataBytes string) bool) *Parser

func (*Parser) Add

func (p *Parser) Add(data string) []Message

func (*Parser) Finish

func (p *Parser) Finish() []Message

func (*Parser) Reset

func (p *Parser) Reset()

func (*Parser) Stream

func (p *Parser) Stream(reader io.Reader, msgBufSize int) <-chan Message

type Writer

type Writer struct {
	// contains filtered or unexported fields
}

func (*Writer) Finish

func (w *Writer) Finish()

func (*Writer) Write

func (w *Writer) Write(p []byte) (n int, err error)