General

This package demonstrates the use of gRPC to store and retrieve potentialy large files. It comprises a client and a server. To upload a file the client has to specified a numeric id and a name, and the server saves it by the given name. To retrieve the file, the client needs to specify the numeric id.

Prerequisites

Building requires

• A fairly recent installation of Google RPC. Versions ≥ 1.8 are expected to work.
• Protobuf that supports version 3 of the format. Versions ≥ 3.5 are expected to work.
• grpc_cpp_plugin
• A POSIX platform. See below tested OSes.
• G++ that supports C++ 14
• bash ≥ 3.2 to run the demo script

The program was tested on the following platforms:

• gRPC v1.18.0, built from source (using Homebrew) on MacOS 10.14 ("Mojave"), using Apple's G++ (actually LLVM), and bash versions 3.2 and 4.4.
• gRPC v1.8 and v1.12 from gRPC's official docker image grpc/cxx (see https://hub.docker.com/r/grpc/cxx). This uses Debian Linux and G++ 6.3 and bash 4.4.

Building

Run:

make clean && make -j4  # Use a higher number of jobs if you prefer

Running

Choose a file on your system to use for the demonsration. The file has to be readable. It will not be otherwise affected. To run the demo script

./demo.sh YOUR_FILE

This will launch the server, upload the file and then retrieve it, and compare the resulting files to the original file.

To run manually:

• Launch the server. Example command to run it in the background:

( cd data && exec ../file_exchange_server ) &

• Launch the client in a working directory other than the one where the server runs e.g.:

# Upload some file from your downloads folder to the server
./file_exchange_client put 1 ~/Downloads/SOME_FILE
# Get the file into the working directory of the file_exchange_client
./file_exchange_client get 1
# Attempt to get a non-existing file, which will cause an error
./file_exchange_client get 9