rga - ripgrep, but also search in PDFs, E-Books, Office documents, zip, tar.gz, etc

rga is a line-oriented search tool that allows you to look for a regex in a multitude of file types. It is a wrapper around the awesome ripgrep that enables it to search in pdf, docx, pptx, movie subtitles (mkv, mp4), sqlite, etc.

Examples

Say you have a large folder of papers or lecture slides, and you can't remember which one of them mentioned LSTMs. With rga, you can just run this:

rga "LSTM|GRU" collection/
[results]

and it will recursively find a regex in pdfs and pptx slides, including if some of them are zipped up.

You can do mostly the same thing with pdfgrep -r, but it will be much slower and you will miss content in other file types.

title: Searching in 20 pdfs with 100 slides each
subtitle: lower is better
data:
   - pdfgrep: 123s
   - rga (first run): 10.3s
   - rga (subsequent runs): 0.1s

On the first run rga is mostly faster because of multithreading, but on subsequent runs (with the same files but any regex query) rga will cache the text extraction because pdf parsing is slow.

Setup

rga should compile with stable Rust. To install it, simply run (your OSes equivalent of)

apt install build-essential pandoc poppler-utils ffmpeg
cargo install ripgrep_all

rga --help # works! :)

You don't necessarily need to install any dependencies, but then you will see an error when trying to read from the corresponding file type (e.g. poppler-utils for pdf).

Technical details

rga simply runs ripgrep (rg) with some options set, especially --pre=rga-preproc and --pre-glob.

rga-preproc [fname] will match an "adapter" to the given file based on either it's filename or it's mime type (if --accurate is given). You can see all adapters currently included in src/adapters.

Some rga adapters run external binaries to do the actual work (such as pandoc or ffmpeg), usually by writing to stdin and reading from stdout. Others use a rust library or bindings to achieve the same effect (like sqlite or zip).

To read archives, the zip and tar libraries are used, which work fully in a streaming fashion - this means that the RAM usage is low and no data is ever actually extracted to disk!

Most adapters read the files from a Read, so they work completely on streamed data (that can come from anywhere including within nested archives).

During the extraction, rga-preproc will compress the data with ZSTD to a memory cache while simultaneously writing it uncompressed to stdout. After completion, if the memory cache is smaller than 2MByte, it is written to a rkv cache

Development

To enable debug logging:

export RUST_LOG=debug
export RUST_BACKTRACE=1

Also rember to disable caching with --rga-no-cache or clear the cache in ~/.cache/rga to debug the adapters.

Future Work

• I wanted to add a photograph adapter (based on object classification / detection) for fun, so you can grep for "mountain" and it will show pictures of mountains, like in Google Photos. It worked with YOLO, but something more useful and state-of-the art like this proved very hard to integrate.
• 7z adapter (couldn't find a nice to use Rust library with streaming)
• allow per-adapter configuration options (probably via env (RGA_ADAPTER_CONF=json))
• maybe use a different disk kv-store as a cache instead of rkv, because I had some weird problems with that. SQLite is great. All other Rust alternatives I could find don't allow writing from multiple processes.
• there's some more (mostly technical) todos in the code I don't know how to fix

Similar tools

• pdfgrep
• this gist has my proof of concept version of a caching extractor to use ripgrep as a replacement for pdfgrep.
• this gist is a more extensive preprocessing script by @ColonolBuendia