Create a mini version of CRAN containing only selected packages

## Introduction

At the end of 2014, CRAN consisted of more than 6,000 packages, and by 2017 this number doubled to more than 12,000. Many organisations need to maintain a private mirror of CRAN, but with only a subset of packages that are relevant to them.

The miniCRAN package makes it possible to create an internally consistent repository consisting of selected packages from CRAN-like repositories. The user specifies a set of desired packages, and miniCRAN recursively reads the dependency tree for these packages, then downloads only this subset.

## Important functions:

Function Use it for
pkgDep() Find package dependencies
makeRepo() Make repository (with or without downloading packages)
addPackage() Add additional packages (and their dependencies) to existing repository
updatePackages() Update the versions of packages currently in the repository

## Installation:

Get the stable version from CRAN:

install.packages("miniCRAN")
library("miniCRAN")

### Development version

Get the latest development version from github:

# Use devtools to install directly from github
library(devtools)
install_github("andrie/miniCRAN")

## Example:

# Determine and download the packages ggplot2, plyr and reshape2,
# including their dependencies:

library("miniCRAN")
pkgs <- c("ggplot2", "plyr", "reshape2")
makeRepo(pkgDep(pkgs), path = file.path(tempdir(), "miniCRAN"))

## Supported by Microsoft

I started this project while employed by Revolution Analytics and Microsoft. Microsoft has kindly agreed that I maintain the project individually, and retains copyright to all work on the project until October 2017.