Add download examples

README.md

@@ -1,9 +1,44 @@
-# OMOP Metadata
+# OMOP Processed Vocabularies
 
-Repository for metadata for working with the [OMOP CDM](https://ohdsi.github.io/CommonDataModel/) at UCLH.
+Repository for pre-processed vocabularies for working with the [OMOP CDM](https://ohdsi.github.io/CommonDataModel/) at UCLH.
 
 You can download these files directly or follow the local development instructions to use git to clone the files
 
+## Downloading versions
+
+You can download a specific tagged version using https.
+in this format, replacing the curly braced values:
+
+`https://github.com/SAFEHR-data/omop-vocabs-processed/raw/refs/tags/{tag}/{relative_path}`
+
+For example for `v4` data file for the `data/version.txt`:
+
+```r
+tag = "v4"
+relative_path = "data/version.txt"
+download_url = glue::glue("https://github.com/SAFEHR-data/omop-vocabs-processed/raw/refs/tags/{tag}/{relative_path}")
+download.file(download_url,
+              destfile = "version.txt",
+              mode = "w")
+```
+
+```python
+import urllib.request
+
+tag = "v4"
+relative_path = "data/version.txt"
+download_url = f"https://github.com/SAFEHR-data/omop-vocabs-processed/raw/refs/tags/{tag}/{relative_path}"
+local_filename = "version.txt"
+
+urllib.request.urlretrieve(download_url, local_filename)
+```
+
+```shell
+export OMOP_METADATA_VERSION=v4
+export OMOP_METADATA_PATH=data/version.txt
+curl -L -o version.txt "https://github.com/SAFEHR-data/omop-vocabs-processed/raw/refs/tags/${OMOP_METADATA_VERSION}/${OMOP_METADATA_PATH}"
+```
+
 ## Local development
 
 If you haven't already set up `git lfs` with your git user account:
@@ -17,13 +52,13 @@ If you haven't already set up `git lfs` with your git user account:
 Clone this repository:
 
 ```shell
-git clone https://github.com/SAFEHR-data/omop-metadata.git
+git clone https://github.com/SAFEHR-data/omop-vocabs-processed.git
 ```
 
 ## Release procedure
 
 1. Update the vocabulary
-2. Update the [data/metadata_version.txt](data/metadata_version.txt) file with this version
+2. Update the [data/version.txt](data/version.txt) file with this version
 3. Tag the release, replacing `${version}` with your version, e.g. `v4`
     ```shell
     git tag ${version}
@@ -32,3 +67,4 @@ git clone https://github.com/SAFEHR-data/omop-metadata.git
     ```shell
     git push --tags origin
     ```
+