Add export book support

.gitignore

@@ -7,6 +7,7 @@ instance/*
 .pytest_cache/*
 .coverage
 testdata/*
+exports/*
 
 calibre/*
 library/*

API.md

@@ -9,6 +9,7 @@ All endpoints are wrappers for `calibredb`
 * [POST Empty Book](#post-empty-book)
 * [PUT Book](#put-book)
 * [DELETE Book](#delete-book)
+* [Export Book](#export-book)
 
 <h3 id="get-book">GET <code>/books/{id}</code></h3>
 
@@ -788,3 +789,71 @@ resp = requests.delete("localhost:5000/books/1")
 
 [Return to top](#)
 </details>
+
+<h3 id="export-book">GET <code>/export/{id}</code></h3>
+
+<details>
+
+<summary>
+    Export book with id
+</summary>
+
+#### Request
+
+* Methods: `GET`
+* Parameters: `id > 0`
+
+#### Responses
+
+##### Success
+
+* Code: `200 OK`
+
+##### Error
+
+* Condition: id is invalid
+* Code: `400 Bad Request`
+* Content:
+
+```json
+{
+    "error": "400 Bad Request: id cannot be <= 0"
+}
+```
+
+* Condition: Book does not exist
+* Code: `404 Not Found`
+* Content:
+
+```json
+{
+    "error": "404 Not Found: No book with id 1 present"
+}
+```
+
+<details>
+<summary>
+    Examples
+</summary>
+<br>
+
+Curl
+
+```console
+$ curl http://localhost:5000/export/1 -o foo.epub
+```
+
+Python
+
+```python
+import requests
+
+resp = requests.get("localhost:5000/export/1", stream=True)
+with open("foo.epub", "wb") as f:
+    for chunk in resp:
+        f.write(chunk)
+```
+</details>
+<br>
+
+[Return to top](#)

README.md

@@ -31,6 +31,9 @@ $ curl --get --data-urlencode "search=title:~^foo.*bar$" \
 # add ebook file to library
 $ curl -X POST -H "Content-Type:multipart/form-data" \
     --form "file=@foo.epub" http://localhost:5000/books
+
+# download ebook from library
+$ curl http://localhost:5000/export/1 -o bar.epub
 ```
 
 See [API.md](API.md) for

calibre_rest/calibre.py

@@ -707,13 +707,41 @@ def _handle_update_flags(self, cmd: str, book: Book = None) -> str:
                 cmd += f" --field {value}"
         return cmd
 
-    def export(self, ids: list[int]) -> str:
-        """Export books from calibre database to filesystem
+    def export(
+        self, ids: list[int], exports_dir: str = "/exports", formats: list[str] = None
+    ) -> None:
+        """Export books from calibre database to filesystem.
 
         Args:
             ids (list[int]): List of book IDs
+            exports_dir (str): Directory to export all files to
+            formats (list[str]): List of formats to export for given id
+
+        Raises:
+            KeyError: when any id does not exist
         """
-        pass
+        for id in ids:
+            validate_id(id)
+
+        cmd = f"{self.cdb_with_lib} export --dont-write-opf --dont-save-cover --single-dir"
+
+        if exports_dir != "":
+            cmd += f" --to-dir={exports_dir}"
+
+        # NOTE: if format does not exist, there is no error
+        if formats is not None:
+            cmd += f" --formats {','.join(formats)}"
+
+        cmd += f' {",".join([str(i) for i in ids])}'
+
+        try:
+            self._run(cmd)
+        except CalibreRuntimeError as e:
+            match = re.search(r"No book with id .* present", e.stderr)
+            if match is not None:
+                raise KeyError(match.group(0)) from e
+            else:
+                raise CalibreRuntimeError from e
 
 
 def join_list(lst: list, sep: str) -> str:

calibre_rest/routes.py

@@ -1,10 +1,11 @@
 import json
+import os
+import os.path as path
 import tempfile
-from os import path
 
 from flask import abort
 from flask import current_app as app
-from flask import jsonify, make_response, request
+from flask import jsonify, make_response, request, send_from_directory
 from werkzeug.exceptions import HTTPException
 from werkzeug.utils import secure_filename
 
@@ -181,10 +182,28 @@ def delete_book(id):
     return response(200, "")
 
 
-# export
-@app.route("/export/<int:id>")
-def export_book(id):
-    pass
+@app.route("/export/<int:id>", methods=["GET"])
+def export_book(id=None):
+    """Export existing book from calibre library to file."""
+    ids = request.args.getlist("id") or None
+    if ids is None:
+        ids = [id]
+
+    with tempfile.TemporaryDirectory() as exports_dir:
+        try:
+            calibredb.export(ids, exports_dir)
+        except KeyError as e:
+            abort(404, e)
+
+        # check exports_dir for files
+        files = [
+            f for f in os.listdir(exports_dir) if path.isfile(path.join(exports_dir, f))
+        ]
+
+        if len(files) <= 0:
+            abort(500)
+        else:
+            return send_from_directory(exports_dir, files[0], as_attachment=True)
 
 
 # export --all

tests/integration/routes_test.py

@@ -593,6 +593,30 @@ def test_update_book_valid_data(url, seed_book):
     assert book["tags"] == ["foo", "bar"]
 
 
+def test_export_book_invalid_id(url):
+    check_error(
+        "GET",
+        f"{url}/export/0",
+        HTTPStatus.BAD_REQUEST,
+        "cannot be <= 0",
+    )
+
+
+def test_export_book_not_exists(url):
+    check_error(
+        "GET",
+        f"{url}/export/10",
+        HTTPStatus.NOT_FOUND,
+        "No book with id",
+    )
+
+
+def test_export_book(url, seed_book):
+    resp = requests.get(f"{url}/export/{seed_book}", stream=True)
+    assert resp.status_code == HTTPStatus.OK
+    assert resp.text == "hello world!\n"
+
+
 def get(url: str, id: int | str, code: IntEnum, mappings: dict = None):
     resp = requests.get(f"{url}/books/{id}")
     assert resp.status_code == code