add support for file_bytes argument with managed_file_context()

camelot/handlers.py

@@ -1,5 +1,7 @@
 # -*- coding: utf-8 -*-
 
+from contextlib import contextmanager
+import io
 import os
 import sys
 
@@ -8,12 +10,13 @@
 from .core import TableList
 from .parsers import Stream, Lattice
 from .utils import (
+    InvalidArguments,
     TemporaryDirectory,
     get_page_layout,
     get_text_objects,
     get_rotation,
     is_url,
-    download_url,
+    get_url_bytes,
 )
 
 
@@ -24,19 +27,33 @@ class PDFHandler(object):
 
     Parameters
     ----------
-    filepath : str
-        Filepath or URL of the PDF file.
+    filepath : str | pathlib.Path, optional (default: None)
+        Filepath or URL of the PDF file. Required if file_bytes is not given
     pages : str, optional (default: '1')
         Comma-separated page numbers.
         Example: '1,3,4' or '1,4-end' or 'all'.
     password : str, optional (default: None)
         Password for decryption.
+    file_bytes : io.IOBase, optional (default: None)
+        A file-like stream. Required if filepath is not given
 
     """
 
-    def __init__(self, filepath, pages="1", password=None):
+    def __init__(self, filepath=None, pages="1", password=None, file_bytes=None):
         if is_url(filepath):
-            filepath = download_url(filepath)
+            file_bytes = get_url_bytes(filepath)
+
+        if not filepath and not file_bytes:
+            raise InvalidArguments('Either `filepath` or `file_bytes` is required')
+        if not filepath:
+            # filepath must either be passed, or taken from the name attribute
+            filepath = getattr(file_bytes, 'name')
+            if not filepath:
+                msg = ('Either pass a `filepath`, or give the '
+                       '`file_bytes` argument a name attribute')
+                raise InvalidArguments(msg)
+        self.file_bytes = file_bytes  # ok to be None
+
         self.filepath = filepath
         if not filepath.lower().endswith(".pdf"):
             raise NotImplementedError("File format not supported")
@@ -49,6 +66,28 @@ def __init__(self, filepath, pages="1", password=None):
                 self.password = self.password.encode("ascii")
         self.pages = self._get_pages(pages)
 
+    @contextmanager
+    def managed_file_context(self):
+        """Reads from either the `filepath` or `file_bytes`
+        attribute of this instance, to return a file-like object.
+        Closes any open file handles on exit or error.
+
+        Returns
+        -------
+        file_bytes : io.IOBase
+            A readable, seekable, file-like object
+        """
+        if self.file_bytes:
+            # if we can't seek, write to a BytesIO object that can,
+            # then seek to the beginning before yielding
+            if not hasattr(self.file_bytes, 'seek'):
+                self.file_bytes = io.BytesIO(self.file_bytes.read())
+            self.file_bytes.seek(0)
+            yield self.file_bytes
+        else:
+            with open(self.filepath, "rb") as file_bytes:
+                yield file_bytes
+
     def _get_pages(self, pages):
         """Converts pages string to list of ints.
 
@@ -71,7 +110,7 @@ def _get_pages(self, pages):
         if pages == "1":
             page_numbers.append({"start": 1, "end": 1})
         else:
-            with open(self.filepath, "rb") as f:
+            with self.managed_file_context() as f:
                 infile = PdfReader(f, strict=False)
 
                 if infile.is_encrypted:
@@ -107,7 +146,7 @@ def _save_page(self, filepath, page, temp):
             Tmp directory.
 
         """
-        with open(filepath, "rb") as fileobj:
+        with self.managed_file_context() as fileobj:
             infile = PdfReader(fileobj, strict=False)
             if infile.is_encrypted:
                 infile.decrypt(self.password)

camelot/io.py

@@ -3,16 +3,21 @@
 import warnings
 
 from .handlers import PDFHandler
-from .utils import validate_input, remove_extra
+from .utils import (
+    InvalidArguments,
+    validate_input,
+    remove_extra,
+)
 
 
 def read_pdf(
-    filepath,
+    filepath=None,
     pages="1",
     password=None,
     flavor="lattice",
     suppress_stdout=False,
     layout_kwargs={},
+    file_bytes=None,
     **kwargs
 ):
     """Read PDF and return extracted tables.
@@ -22,8 +27,8 @@ def read_pdf(
 
     Parameters
     ----------
-    filepath : str
-        Filepath or URL of the PDF file.
+    filepath : str | pathlib.Path, optional (default: None)
+        Filepath or URL of the PDF file. Required if file_bytes is not given
     pages : str, optional (default: '1')
         Comma-separated page numbers.
         Example: '1,3,4' or '1,4-end' or 'all'.
@@ -34,6 +39,8 @@ def read_pdf(
         Lattice is used by default.
     suppress_stdout : bool, optional (default: True)
         Print all logs and warnings.
+    file_bytes : io.IOBase, optional (default: None)
+        A file-like stream. Required if filepath is not given
     layout_kwargs : dict, optional (default: {})
         A dict of `pdfminer.layout.LAParams <https://github.com/euske/pdfminer/blob/master/pdfminer/layout.py#L33>`_ kwargs.
     table_areas : list, optional (default: None)
@@ -103,12 +110,15 @@ def read_pdf(
             "Unknown flavor specified." " Use either 'lattice' or 'stream'"
         )
 
+    if not filepath and not file_bytes:
+        raise InvalidArguments('Either `filepath` or `file_bytes` is required')
+
     with warnings.catch_warnings():
         if suppress_stdout:
             warnings.simplefilter("ignore")
 
         validate_input(kwargs, flavor=flavor)
-        p = PDFHandler(filepath, pages=pages, password=password)
+        p = PDFHandler(filepath, pages=pages, password=password, file_bytes=file_bytes)
         kwargs = remove_extra(kwargs, flavor=flavor)
         tables = p.parse(
             flavor=flavor,

camelot/utils.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-import os
+import io
 import re
 import random
 import shutil
@@ -36,6 +36,10 @@
 _VALID_URLS.discard("")
 
 
+class InvalidArguments(Exception):
+    pass
+
+
 # https://github.com/pandas-dev/pandas/blob/master/pandas/io/common.py
 def is_url(url):
     """Check to see if a URL has a valid protocol.
@@ -66,31 +70,30 @@ def random_string(length):
     return ret
 
 
-def download_url(url):
-    """Download file from specified URL.
+def get_url_bytes(url):
+    """Get a stream of bytes for url
 
     Parameters
     ----------
     url : str or unicode
 
     Returns
     -------
-    filepath : str or unicode
-        Temporary filepath.
+    file_bytes : io.BytesIO
+        a file-like object that cane be read
 
     """
-    filename = f"{random_string(6)}.pdf"
-    with tempfile.NamedTemporaryFile("wb", delete=False) as f:
-        headers = {"User-Agent": "Mozilla/5.0"}
-        request = Request(url, None, headers)
-        obj = urlopen(request)
-        content_type = obj.info().get_content_type()
-        if content_type != "application/pdf":
-            raise NotImplementedError("File format not supported")
-        f.write(obj.read())
-    filepath = os.path.join(os.path.dirname(f.name), filename)
-    shutil.move(f.name, filepath)
-    return filepath
+    file_bytes = io.BytesIO()
+    file_bytes.name = url
+    headers = {"User-Agent": "Mozilla/5.0"}
+    request = Request(url, data=None, headers=headers)
+    obj = urlopen(request)
+    content_type = obj.info().get_content_type()
+    if content_type != "application/pdf":
+        raise NotImplementedError("File format not supported")
+    file_bytes.write(obj.read())
+    file_bytes.seek(0)
+    return file_bytes
 
 
 stream_kwargs = ["columns", "edge_tol", "row_tol", "column_tol"]

tests/test_common.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 
+import io
 import os
 import sys
 
@@ -172,3 +173,20 @@ def test_handler_pages_generator():
 
     handler = PDFHandler(filename)
     assert handler._get_pages("1,2,5-10") == [1, 2, 5, 6, 7, 8, 9, 10]
+
+
+def test_from_open():
+    filename = os.path.join(testdir, "foo.pdf")
+    with open(filename, "rb") as file_bytes:
+        tables = camelot.read_pdf(file_bytes=file_bytes)
+        assert repr(tables) == "<TableList n=1>"
+        assert repr(tables[0]) == "<Table shape=(7, 7)>"
+
+def test_from_bytes():
+    filename = os.path.join(testdir, "foo.pdf")
+    file_bytes = io.BytesIO()
+    with open(filename, "rb") as f:
+        file_bytes.write(f.read())  # note that we didn't seek, done by PDFHandler
+    tables = camelot.read_pdf(file_bytes=file_bytes)
+    assert repr(tables) == "<TableList n=1>"
+    assert repr(tables[0]) == "<Table shape=(7, 7)>"