Add API to get formats

src/calibre/db/backend.py

@@ -859,8 +859,8 @@ class DB(object):
             ans['mtime'] = utcfromtimestamp(stat.st_mtime)
         return ans
 
-    def has_format(self, book_id, fmt):
+    def has_format(self, book_id, fmt, fname, path):
-        return self.format_abspath(book_id, fmt) is not None
+        return self.format_abspath(book_id, fmt, fname, path) is not None
 
     def copy_cover_to(self, path, dest, windows_atomic_move=None, use_hardlink=False):
         path = os.path.join(self.library_path, path, 'cover.jpg')
@@ -896,5 +896,33 @@ class DB(object):
                         return True
         return False
 
+    def copy_format_to(self, book_id, fmt, fname, path, dest,
+                       windows_atomic_move=None, use_hardlink=False):
+        path = self.format_abspath(book_id, fmt, fname, path)
+        if path is None:
+            return False
+        if windows_atomic_move is not None:
+            if not isinstance(dest, basestring):
+                raise Exception("Error, you must pass the dest as a path when"
+                        " using windows_atomic_move")
+            if dest and not samefile(dest, path):
+                windows_atomic_move.copy_path_to(path, dest)
+        else:
+            if hasattr(dest, 'write'):
+                with lopen(path, 'rb') as f:
+                    shutil.copyfileobj(f, dest)
+                if hasattr(dest, 'flush'):
+                    dest.flush()
+            elif dest and not samefile(dest, path):
+                if use_hardlink:
+                    try:
+                        hardlink_file(path, dest)
+                        return True
+                    except:
+                        pass
+                with lopen(path, 'rb') as f, lopen(dest, 'wb') as d:
+                    shutil.copyfileobj(f, d)
+        return True
+
    # }}}
 

src/calibre/db/cache.py

@@ -15,12 +15,14 @@ from functools import wraps, partial
 from calibre.db import SPOOL_SIZE
 from calibre.db.categories import get_categories
 from calibre.db.locking import create_locks, RecordLock
+from calibre.db.errors import NoSuchFormat
 from calibre.db.fields import create_field
 from calibre.db.search import Search
 from calibre.db.tables import VirtualTable
 from calibre.db.lazy import FormatMetadata, FormatsList
 from calibre.ebooks.metadata.book.base import Metadata
-from calibre.ptempfile import PersistentTemporaryFile, SpooledTemporaryFile
+from calibre.ptempfile import (base_dir, PersistentTemporaryFile,
+                               SpooledTemporaryFile)
 from calibre.utils.date import now
 from calibre.utils.icu import sort_key
 
@@ -106,27 +108,6 @@ class Cache(object):
     def field_metadata(self):
         return self.backend.field_metadata
 
-    def _format_abspath(self, book_id, fmt):
-        '''
-        Return absolute path to the ebook file of format `format`
-
-        WARNING: This method will return a dummy path for a network backend DB,
-        so do not rely on it, use format(..., as_path=True) instead.
-
-        Currently used only in calibredb list, the viewer and the catalogs (via
-        get_data_as_dict()).
-
-        Apart from the viewer, I don't believe any of the others do any file
-        I/O with the results of this call.
-        '''
-        try:
-            name = self.fields['formats'].format_fname(book_id, fmt)
-            path = self._field_for('path', book_id).replace('/', os.sep)
-        except:
-            return None
-        if name and path:
-            return self.backend.format_abspath(book_id, fmt, name, path)
-
     def _get_metadata(self, book_id, get_user_categories=True): # {{{
         mi = Metadata(None, template_cache=self.formatter_template_cache)
         author_ids = self._field_ids_for('authors', book_id)
@@ -421,7 +402,7 @@ class Cache(object):
         return ret
 
     @api
-    def copy_cover_to(self, book_id, dest):
+    def copy_cover_to(self, book_id, dest, use_hardlink=False):
         '''
         Copy the cover to the file like object ``dest``. Returns False
         if no cover exists or dest is the same file as the current cover.
@@ -436,7 +417,148 @@ class Cache(object):
                 return False
 
         with self.record_lock.lock(book_id):
-            return self.backend.copy_cover_to(path, dest)
+            return self.backend.copy_cover_to(path, dest,
+                                              use_hardlink=use_hardlink)
+
+    @api
+    def copy_format_to(self, book_id, fmt, dest, use_hardlink=False):
+        '''
+        Copy the format ``fmt`` to the file like object ``dest``. If the
+        specified format does not exist, raises :class:`NoSuchFormat` error.
+        dest can also be a path, in which case the format is copied to it, iff
+        the path is different from the current path (taking case sensitivity
+        into account).
+        '''
+        with self.read_lock:
+            try:
+                name = self.fields['formats'].format_fname(book_id, fmt)
+                path = self._field_for('path', book_id).replace('/', os.sep)
+            except:
+                raise NoSuchFormat('Record %d has no %s file'%(book_id, fmt))
+
+        with self.record_lock.lock(book_id):
+            return self.backend.copy_format_to(book_id, fmt, name, path, dest,
+                                               use_hardlink=use_hardlink)
+
+    @read_api
+    def format_abspath(self, book_id, fmt):
+        '''
+        Return absolute path to the ebook file of format `format`
+
+        Currently used only in calibredb list, the viewer and the catalogs (via
+        get_data_as_dict()).
+
+        Apart from the viewer, I don't believe any of the others do any file
+        I/O with the results of this call.
+        '''
+        try:
+            name = self.fields['formats'].format_fname(book_id, fmt)
+            path = self._field_for('path', book_id).replace('/', os.sep)
+        except:
+            return None
+        if name and path:
+            return self.backend.format_abspath(book_id, fmt, name, path)
+
+    @read_api
+    def has_format(self, book_id, fmt):
+        'Return True iff the format exists on disk'
+        try:
+            name = self.fields['formats'].format_fname(book_id, fmt)
+            path = self._field_for('path', book_id).replace('/', os.sep)
+        except:
+            return False
+        return self.backend.has_format(book_id, fmt, name, path)
+
+    @read_api
+    def formats(self, book_id, verify_formats=True):
+        '''
+        Return tuple of all formats for the specified book. If verify_formats
+        is True, verifies that the files exist on disk.
+        '''
+        ans = self.field_for('formats', book_id)
+        if verify_formats and ans:
+            try:
+                path = self._field_for('path', book_id).replace('/', os.sep)
+            except:
+                return ()
+            def verify(fmt):
+                try:
+                    name = self.fields['formats'].format_fname(book_id, fmt)
+                except:
+                    return False
+                return self.backend.has_format(book_id, fmt, name, path)
+
+            ans = tuple(x for x in ans if verify(x))
+        return ans
+
+    @api
+    def format(self, book_id, fmt, as_file=False, as_path=False, preserve_filename=False):
+        '''
+        Return the ebook format as a bytestring or `None` if the format doesn't exist,
+        or we don't have permission to write to the ebook file.
+
+        :param as_file: If True the ebook format is returned as a file object. Note
+                        that the file object is a SpooledTemporaryFile, so if what you want to
+                        do is copy the format to another file, use :method:`copy_format_to`
+                        instead for performance.
+        :param as_path: Copies the format file to a temp file and returns the
+                        path to the temp file
+        :param preserve_filename: If True and returning a path the filename is
+                                  the same as that used in the library. Note that using
+                                  this means that repeated calls yield the same
+                                  temp file (which is re-created each time)
+        '''
+        with self.read_lock:
+            ext = ('.'+fmt.lower()) if fmt else ''
+            try:
+                fname = self.fields['formats'].format_fname(book_id, fmt)
+            except:
+                return None
+            fname += ext
+
+        if as_path:
+            if preserve_filename:
+                bd = base_dir()
+                d = os.path.join(bd, 'format_abspath')
+                try:
+                    os.makedirs(d)
+                except:
+                    pass
+                ret = os.path.join(d, fname)
+                with self.record_lock.lock(book_id):
+                    try:
+                        self.copy_format_to(book_id, fmt, ret)
+                    except NoSuchFormat:
+                        return None
+            else:
+                with PersistentTemporaryFile(ext) as pt, self.record_lock.lock(book_id):
+                    try:
+                        self.copy_format_to(book_id, fmt, pt)
+                    except NoSuchFormat:
+                        return None
+                    ret = pt.name
+        elif as_file:
+            ret = SpooledTemporaryFile(SPOOL_SIZE)
+            with self.record_lock.lock(book_id):
+                try:
+                    self.copy_format_to(book_id, fmt, ret)
+                except NoSuchFormat:
+                    return None
+            ret.seek(0)
+            # Various bits of code try to use the name as the default
+            # title when reading metadata, so set it
+            ret.name = fname
+        else:
+            buf = BytesIO()
+            with self.record_lock.lock(book_id):
+                try:
+                    self.copy_format_to(book_id, fmt, buf)
+                except NoSuchFormat:
+                    return None
+
+            ret = buf.getvalue()
+
+        return ret
 
     @read_api
     def multisort(self, fields, ids_to_sort=None):

src/calibre/db/tests/reading.py

@@ -195,7 +195,7 @@ class ReadingTest(BaseTest):
         'Test cover() returns the same data for both backends'
         from calibre.library.database2 import LibraryDatabase2
         old = LibraryDatabase2(self.library_path)
-        covers = {i: old.cover(i, index_is_id=True) for i in (1, 2, 3)}
+        covers = {i: old.cover(i, index_is_id=True) for i in old.all_ids()}
         old = None
         cache = self.init_cache(self.library_path)
         for book_id, cdata in covers.iteritems():
@@ -303,6 +303,38 @@ class ReadingTest(BaseTest):
 
     # }}}
 
+    def test_get_formats(self): # {{{
+        'Test reading ebook formats using the format() method'
+        from calibre.library.database2 import LibraryDatabase2
+        old = LibraryDatabase2(self.library_path)
+        ids = old.all_ids()
+        lf = {i:set(old.formats(i, index_is_id=True).split(',')) if old.formats(
+            i, index_is_id=True) else set() for i in ids}
+        formats = {i:{f:old.format(i, f, index_is_id=True) for f in fmts} for
+                   i, fmts in lf.iteritems()}
+        old = None
+        cache = self.init_cache(self.library_path)
+        for book_id, fmts in lf.iteritems():
+            self.assertEqual(fmts, set(cache.formats(book_id)),
+                             'Set of formats is not the same')
+            for fmt in fmts:
+                old = formats[book_id][fmt]
+                self.assertEqual(old, cache.format(book_id, fmt),
+                                 'Old and new format disagree')
+                f = cache.format(book_id, fmt, as_file=True)
+                self.assertEqual(old, f.read(),
+                                 'Failed to read format as file')
+                with open(cache.format(book_id, fmt, as_path=True,
+                                       preserve_filename=True), 'rb') as f:
+                    self.assertEqual(old, f.read(),
+                                 'Failed to read format as path')
+                with open(cache.format(book_id, fmt, as_path=True), 'rb') as f:
+                    self.assertEqual(old, f.read(),
+                                 'Failed to read format as path')
+
+
+    # }}}
+
 def tests():
     return unittest.TestLoader().loadTestsFromTestCase(ReadingTest)