Title:	Parse Server-Sent Events
Version:	0.1.0
Description:	Functionality to parse server-sent events with a high-level interface that can be extended for custom applications.
License:	MIT + file LICENSE
URL:	https://github.com/calderonsamuel/SSEparser, https://calderonsamuel.github.io/SSEparser/
BugReports:	https://github.com/calderonsamuel/SSEparser/issues
Imports:	magrittr, purrr, R6, rlang, stringr
Suggests:	jsonlite, testthat (≥ 3.0.0)
Config/testthat/edition:	3
Encoding:	UTF-8
RoxygenNote:	7.2.3
NeedsCompilation:	no
Packaged:	2023-12-14 11:32:34 UTC; Samuel
Author:	Samuel Calderon [aut, cre, cph]
Maintainer:	Samuel Calderon <samuel.calderon@uarm.pe>
Repository:	CRAN
Date/Publication:	2023-12-14 16:30:06 UTC

Pipe operator

Description

See magrittr::%>% for details.

Usage

lhs %>% rhs

Arguments

Value

The result of calling rhs(lhs).

Parse a Server Sent Event

Description

This class can help you parse a single server sent event or a stream of them. You can inherit the class for a custom application. The parse_sse() function wraps this class for a more functional approach.

Details

The HTML specification tells us that event streams are composed by chunks (also called blocks, or messages) and lines. A single new line character (⁠\n⁠) states the end of a line, and two consecutive new line characters (⁠\n\n⁠) state the end of a chunk.

This means that, in practice, an event can be composed of one or more chunks, and a chunk can be composed of one or more lines.

data: This is the first chunk, it has one line

data: This is the second chunk
extra: It has two lines

data: This is the third chunk, it has an id field. This is common.
id: 123

: Lines that start with a colon are comments, they will be ignored
data: This is the forth chunk, it has a comment

data: This is the fifth chunk. Normally you will receive a data field
custom: But the server can send custom field names. SSEparser parses them too.

Typically, an event stream will send a single chunk for event, but it is important to understand that event != chunk because SSEparser$events will be a list of all the chunks received as it makes a more consistent output.

Value

An object with R6 class SSEparser

Public fields

Methods

Public methods

• SSEparser$append_parsed_sse()

• SSEparser$parse_sse()

• SSEparser$new()

• SSEparser$clone()

Method append_parsed_sse()

Takes a parsed event and appends it to the events field. You can overwrite this method if you decide to extend this class.

Usage

SSEparser$append_parsed_sse(parsed_event)

Arguments

Method parse_sse()

Takes a string that comes from a server sent event and parses it to an R list. You should never overwrite this method.

Usage

SSEparser$parse_sse(event)

Arguments

Method new()

Create a new SSE parser

Usage

SSEparser$new()

Method clone()

The objects of this class are cloneable with this method.

Usage

SSEparser$clone(deep = FALSE)

Arguments

Examples

example_event <- 
"data: This is the first chunk, it has one line

data: This is the second chunk
extra: It has two lines

data: This is the third chunk, it has an id field. This is common.
id: 123

: Lines that start with a colon are comments, they will be ignored
data: This is the fourth chunk, it has a comment

data: This is the fifth chunk. Normally you will receive a data field
custom: But the server can send custom field names. SSEparser parses them too."
 
parser <- SSEparser$new()
parser$parse_sse(example_event)
 
str(parser$events)

Parse Server-Sent Events

Description

This functions converts Server-Sent Events to a R list. This a wrapper function for the lower level SSEparser R6 class. A single string can contain multiple SSEs.

Usage

parse_sse(event)

Arguments

Value

An R list on which each element is an event

Examples

event <- "data: test\nevent: message\nid: 123\n\n"
parse_sse(event)

with_comment <- "data: test\n: comment\nevent: example\n\n"
parse_sse(with_comment)