The goal of lzstring-r is to provide an R wrapper for the lzstring C++ library. lzstring is originally a JavaScript library that provides fast and efficient string compression and decompression using a LZ-based algorithm.
Credit goes to Winston Chang for spotting this missing R package and guiding me over at the R Shinylive repoâcheck out his awesome contributions which this repo is based on here and here. Also, shoutout to Andy Kras for his implementation in C++ of lzstring, which you can find right here, and pieroxy, the original brain behind lzstring in JavaScriptâpeek at his work over here.
InstallationYou can install the released version of lzstring from CRAN with:
install.packages("lzstring")
Or the development version from GitHub:
# install.packages("devtools")
devtools::install_github("parmsam/lzstring-r")
Usage Basic Example
library(lzstring)
# Text data
message <- "The quick brown fox jumps over the lazy dog!"
compressed <- lzstring::compressToBase64(message)
compressed
#> [1] "CoCwpgBAjgrglgYwNYQEYCcD2B3AdhAM0wA8IArGAWwAcBnCTANzHQgBdwIAbAQwC8AnhAAmmAOYBCIA"
decompressed <- lzstring::decompressFromBase64(compressed)
cat(decompressed)
#> The quick brown fox jumps over the lazy dog!
Compressing and Decompressing JSON
json_data <- list(name = "John Doe", age = 30, email = "john.doe@example.com")
json_string <- jsonlite::toJSON(json_data)
compressed <- lzstring::compressToBase64(json_string)
compressed
#> [1] "N4IgdghgtgpiBcBtEApA9gCzAAgCJrgF0AaECAcziQGYAGEkGKCASwBsFkArTMAOgAmBAAIwAHtAAObGHwDGaKCEIBfIA==="
decompressed <- lzstring::decompressFromBase64(compressed)
identical(json_string, decompressed)
#> [1] FALSE
cat(decompressed)
#> {"name":["John Doe"],"age":[30],"email":["john.doe@example.com"]}
Round-Trip for Complex R Objects
Note: Always serialize complex R objects (lists, data frames, etc.) to JSON before compressing. After decompression, deserialize back to R.
obj <- list(a = 1, b = "text", c = list(x = 1:3))
json <- jsonlite::serializeJSON(obj)
lz <- lzstring::compressToBase64(json)
json2 <- lzstring::decompressFromBase64(lz)
obj2 <- jsonlite::unserializeJSON(json2)
identical(obj, obj2) # TRUE
#> [1] TRUE
R Code Example
r_code <- '
library(dplyr)
data <- data.frame(
name = c("John", "Jane", "Jake"),
age = c(28, 22, 32),
salary = c(50000, 60000, 55000)
)
# Filter data for age greater than 25
filtered_data <- filter(data, age > 25)
# Add a new column with updated salary
data <- mutate(data, updated_salary = salary * 1.05)
'
compressed <- lzstring::compressToBase64(r_code)
compressed
#> [1] "FAGwlgRgTghlCeAKAJgBxPKBKYxkwBcYACAHgFpj8iA6AM1gFsBTRYY4gOxheIF5iAY0QAiAFIB7ABacRAGmLiYnZvMViYAa1VY57YjADmzfkMQAmABwLz5hQGZzu/QGcYIOPFPCArAAYAvwUANkCg4h9/AJwcYABiYgAxMBACZigqQhI6CQyjE0MoZkJ04gIpZWJzH2A6FLSi5AB9ahIKYjrU9JQshXziAD4qn1iEgEFkZAMuZgB3IQkQAFdGTmJZsHLiJdRqZim3DwQ8LLJKRiWiNJ6iBR295sPPUyeEYgAqYgBGGj8R4CAA=="
decompose <- lzstring::decompressFromBase64(compressed)
cat(decompose)
#>
#> library(dplyr)
#>
#> data <- data.frame(
#> name = c("John", "Jane", "Jake"),
#> age = c(28, 22, 32),
#> salary = c(50000, 60000, 55000)
#> )
#>
#> # Filter data for age greater than 25
#> filtered_data <- filter(data, age > 25)
#>
#> # Add a new column with updated salary
#> data <- mutate(data, updated_salary = salary * 1.05)
Compress Shinylive Hashes
code <- 'library(shiny)
ui <- fluidPage(
"Hello, world!"
)
server <- function(input, output, session) {
}
shinyApp(ui, server)'
files <- list(
name = jsonlite::unbox("app.R"),
content = jsonlite::unbox(code)
)
files_json <- jsonlite::toJSON(list(files))
files_lz <- lzstring::compressToEncodedURIComponent(as.character(files_json))
cat(paste0("https://shinylive.io/r/app/#code=", files_lz))
#> https://shinylive.io/r/app/#code=NobwRAdghgtgpmAXGKAHVA6ASmANGAYwHsIAXOMpMAGwEsAjAJykYE8AKAZwAtaJWAlAB0IAV1oACADwBaCQDNq4gCYAFKAHM47ERIlCwACTjVqRXBIDuRRtWUBCAyOEROcRgDd30ufNEQCUloSdj5UUVILIgjwyIk3Tk5giAEJEBEAXxEePlYAQXR2cQs3T3cBMAyAXSA
Decompress Shinylive Hashes
x <- lzstring::decompressFromEncodedURIComponent("NobwRAdghgtgpmAXGKAHVA6VBPMAaMAYwHsIAXOcpMAMwCdiYACAZwAsBLCbDOAD1R04LFkw4xUxOmTERUAVzJ4mQiABM4dZfI4AdCPp0YuCsgH0WAGw4a6ACl2RHyxwDlnTAAzKAjJ+9MAEyeAJT64RAAAqq2GBR8ZPoaNExkCXYhiPpMOSpwZPJ0EEw0jhAAVIFioiAmihgQGUzlQQC+jvpgrQC6QA")
y <- jsonlite::fromJSON(x)
cat(y$name)
#> app.py
cat(y$content)
#> from shiny.express import input, render, ui
#>
#> ui.input_slider("n", "N", 0, 100, 20)
#>
#>
#> @render.text
#> def txt():
#> return f"n*2 is {input.n() * 2}"
Encoding and Limitations
Why do I get an empty string after decompressing?
This may happen if the input was not properly encoded, or if the compressed string is corrupted.
Why does my decompressed JSON fail to parse?
Ensure you serialize your R object to JSON (or use serializeJSON
) before compressing.
Can I compress binary data?
Encode it as base64 or hex first, then compress the resulting string.
@examples
tag and creates a URL to the shinylive.io service. During documentation build, a new section is added to the function manual containing the link and an iframe to the application itself.RetroSearch is an open source project built by @garambo | Open a GitHub Issue
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