Add git version to /api endpoint response

[Copilot]

This PR adds the current git revision hash to the /api endpoint response, allowing clients to identify which version of the code is running.

Changes

API Response

The /api endpoint now includes a version field at the root level of the response:

{
  "version": "779cdb5",
  "http://example.com/api": {
    "description": "List all APIs"
  },
  "http://example.com/api/:id/manifest.json": {
    "description": "Generate readium manifest for resource",
    "args": {"source": ["ia", "ol"], "format": ["epub", "pdf"]}
  }
}

Implementation Details

prs/routes/api.py:

• Added get_git_revision_short_hash() function that uses subprocess.check_output() to execute git rev-parse --short HEAD
• Returns the 7-character short commit hash, or None if git is unavailable
• Uses only Python standard library (subprocess)
• Updated apis() endpoint to call this function and include the version in the response

docker/Dockerfile:

• Added git installation to ensure the git executable is available at runtime
• Uses apt-get with --no-install-recommends to minimize image size

Benefits

• Runtime version identification: Easily identify which commit is deployed
• No hardcoded values: Version is queried dynamically from the git repository
• Minimal dependencies: Uses only Python standard library, no additional Python packages required
• Graceful degradation: Returns null if git is not available instead of crashing

The .git directory is already mounted in the container via the compose.yaml volume mapping (.:/app), so the git repository is accessible at runtime.

Original prompt

Update the /api endpoint so that it includes the current version of the code (the short git revision hash). Do not hardcode or write the value to a file; instead, query it from the project's git repository at runtime. Avoid introducing large dependencies—this should use only the Python standard library. The version should be included in the root /api response. Ensure the required package (git executable) is available, but do not add non-stdlib dependencies to requirements.txt or similar. Tests do not need to be updated for this small change.

The following is the updated code for prs/routes/api.py:

#!/usr/bin/env python

"""
API routes for PRS,

:copyright: (c) 2025 by AUTHORS
:license: see LICENSE for more details

"""

import base64
import requests
import internetarchive as ia
from urllib.parse import quote
from fastapi import (
APIRouter,
Request,
HTTPException,
status
)
from fastapi.responses import HTMLResponse, RedirectResponse, Response
from prs.configs import BASE_URL, PORT, READIUM_HOST_PORT
import subprocess

router = APIRouter()

def get_git_revision_short_hash():
try:
return subprocess.check_output(
["git", "rev-parse", "--short", "HEAD"],
cwd=None
).decode("ascii").strip()
except Exception:
return None

def ia_get_epub_filepath(item_id):
if '$' in item_id:
item_id, filepath = item_id.replace('$', '/').split('/', 1)
else:
item = ia.get_item(item_id)
for file in item.files:
if file['name'].endswith('.epub'):
filepath = file['name']
return f"https://archive.org/download/{item_id}/{filepath}"

def ol_get_epub_filepath(olid):
# fetch olid from openlibrary and get url (if ends with epub)
pass

def encode_book_path(source: str, book_id: str) -> str:
source_to_filepath = {
"ia": ia_get_epub_filepath,
#"ol": lambda: f"" # use openlibrary.org/search.json to get url of ebook
}
filepath = source_to_filepathsource
encoded_filepath = base64.b64encode(filepath.encode()).decode()
return encoded_filepath.replace('/', '_').replace('+', '-').replace('=', '')

def prs_uri(request: Request):
if host := request.headers.get('x-forwarded-host'):
return f"{request.url.scheme}://{host}{BASE_URL}"
port = f":{PORT}" if PORT not in {80, 443} else ""
return f"{request.url.scheme}://{request.url.hostname}{port}{BASE_URL}"

@router.get('/', status_code=status.HTTP_200_OK)
async def apis(request: Request):
version = get_git_revision_short_hash()
return {
"version": version,
f"{prs_uri(request)}/api": {
"description": "List all APIs",
},
f"{prs_uri(request)}/api/:id/manifest.json": {
"description": "Generate readium manifest for resource",
"args": {"source": ["ia", "ol"], "format": ["epub", "pdf"]}
}
}

@router.get("/{source}/{book_id}/read")
async def redirect_reader(request: Request, source: str, book_id: str):
manifest_url = f"{prs_uri(request)}/api/{source}/{book_id}/manifest.json"
manifest_uri = quote(manifest_url, safe='')
return RedirectResponse(f"https://playground.readium.org/read/manifest/{manifest_uri}")

@router.get("/{source}/{book_id}/manifest.json")
async def get_manifest(request: Request, source: str, book_id: str):
def patch_manifest(manifest):
manifest_uri = f"{prs_uri(request)}/api/{source}/{book_id}/manifest.json"
encoded_manifest_uri = quote(manifest_uri, safe='')
for i in range(len(manifest['links'])):
if manifest['links'][i].get('rel') == 'self':
manifest['links'][i]['href'] = encoded_manifest_uri
return manifest

# TODO: s3 permission/auth checks go here for protected epubs, or decorate this route

readium_uri = f"http://{READIUM_HOST_PORT}/{encode_book_path(source, book_id)}/manifest.json"
manifest = requests.get(readium_uri).json()
return patch_manifest(manifest)

Proxy for all other readium requests

@router.get("/{source}/{book_id}/{readium_uri:path}")
async def proxy_readium(request: Request, source: str, book_id: str, readium_uri: str, format: str=".epub"):
# TODO: permission/auth checks go here, or decorate this route
readium_url = f"http://{READIUM_HOST_PORT}/{encode_book_path(source, book_id)}/{readium_uri}"
r = requests.get(readium_url, params=dict(request.query_params))
if readium_url.endswith('.json'):
return r.json()
content_type = r.headers.get("Content-Type", "application/octet-stream")
return Response(content=r.content, media_type=content_type)

*This pull request was created as a result of the following prompt from Copilot chat.* > Update the /api endpoint so that it includes the current version of the code (the short git revision hash). Do not hardcode or write the value to a file; instead, query it from the project's git repository at runtime. Avoid introducing large dependencies—this should use only the Python standard library. The version should be included in the root /api response. Ensure the required package (git executable) is available, but do not add non-stdlib dependencies to requirements.txt or similar. Tests do not need to be updated for this small change. > > The following is the updated code for prs/routes/api.py: > > #!/usr/bin/env python > > """ > API routes for PRS, > > ©️ (c) 2025 by AUTHORS > :license: see LICENSE for more details > """ > > import base64 > import requests > import internetarchive as ia > from urllib.parse import quote > from fastapi import ( > APIRouter, > Request, > HTTPException, > status > ) > from fastapi.responses import HTMLResponse, RedirectResponse, Response > from prs.configs import BASE_URL, PORT, READIUM_HOST_PORT > import subprocess > > router = APIRouter() > > def get_git_revision_short_hash(): > try: > return subprocess.check_output( > ["git", "rev-parse", "--short", "HEAD"], > cwd=None > ).decode("ascii").strip() > except Exception: > return None > > def ia_get_epub_filepath(item_id): > if '$' in item_id: > item_id, filepath = item_id.replace('$', '/').split('/', 1) > else: > item = ia.get_item(item_id) > for file in item.files: > if file['name'].endswith('.epub'): > filepath = file['name'] > return f"https://archive.org/download/{item_id}/{filepath}" > > def ol_get_epub_filepath(olid): > # fetch olid from openlibrary and get url (if ends with epub) > pass > > def encode_book_path(source: str, book_id: str) -> str: > source_to_filepath = { > "ia": ia_get_epub_filepath, > #"ol": lambda: f"" # use openlibrary.org/search.json to get url of ebook > } > filepath = source_to_filepath[source](book_id) > encoded_filepath = base64.b64encode(filepath.encode()).decode() > return encoded_filepath.replace('/', '_').replace('+', '-').replace('=', '') > > def prs_uri(request: Request): > if host := request.headers.get('x-forwarded-host'): > return f"{request.url.scheme}://{host}{BASE_URL}" > port = f":{PORT}" if PORT not in {80, 443} else "" > return f"{request.url.scheme}://{request.url.hostname}{port}{BASE_URL}" > > @router.get('/', status_code=status.HTTP_200_OK) > async def apis(request: Request): > version = get_git_revision_short_hash() > return { > "version": version, > f"{prs_uri(request)}/api": { > "description": "List all APIs", > }, > f"{prs_uri(request)}/api/:id/manifest.json": { > "description": "Generate readium manifest for resource", > "args": {"source": ["ia", "ol"], "format": ["epub", "pdf"]} > } > } > > @router.get("/{source}/{book_id}/read") > async def redirect_reader(request: Request, source: str, book_id: str): > manifest_url = f"{prs_uri(request)}/api/{source}/{book_id}/manifest.json" > manifest_uri = quote(manifest_url, safe='') > return RedirectResponse(f"https://playground.readium.org/read/manifest/{manifest_uri}") > > @router.get("/{source}/{book_id}/manifest.json") > async def get_manifest(request: Request, source: str, book_id: str): > def patch_manifest(manifest): > manifest_uri = f"{prs_uri(request)}/api/{source}/{book_id}/manifest.json" > encoded_manifest_uri = quote(manifest_uri, safe='') > for i in range(len(manifest['links'])): > if manifest['links'][i].get('rel') == 'self': > manifest['links'][i]['href'] = encoded_manifest_uri > return manifest > > # TODO: s3 permission/auth checks go here for protected epubs, or decorate this route > > readium_uri = f"http://{READIUM_HOST_PORT}/{encode_book_path(source, book_id)}/manifest.json" > manifest = requests.get(readium_uri).json() > return patch_manifest(manifest) > > # Proxy for all other readium requests > @router.get("/{source}/{book_id}/{readium_uri:path}") > async def proxy_readium(request: Request, source: str, book_id: str, readium_uri: str, format: str=".epub"): > # TODO: permission/auth checks go here, or decorate this route > readium_url = f"http://{READIUM_HOST_PORT}/{encode_book_path(source, book_id)}/{readium_uri}" > r = requests.get(readium_url, params=dict(request.query_params)) > if readium_url.endswith('.json'): > return r.json() > content_type = r.headers.get("Content-Type", "application/octet-stream") > return Response(content=r.content, media_type=content_type) >

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