X-Git-Url: http://gitweb.pimeys.fr/?p=NK2015_Client_Python_Alpha.git;a=blobdiff_plain;f=rsa_source%2Frsa%2Fpem.py;fp=rsa_source%2Frsa%2Fpem.py;h=9ea9f031a035ccb1be233129700c78aa55765703;hp=0000000000000000000000000000000000000000;hb=76e06d82c94bcb814b95419c7faaeacf4beb0155;hpb=d621c5224a44dc20bc2aaf661954fd1df65dd147

diff --git a/rsa_source/rsa/pem.py b/rsa_source/rsa/pem.py
new file mode 100644
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+++ b/rsa_source/rsa/pem.py
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+# -*- coding: utf-8 -*-
+#
+#  Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+'''Functions that load and write PEM-encoded files.'''
+
+import base64
+
+def _markers(pem_marker):
+    '''Returns the start and end PEM markers
+
+    >>> _markers('RSA PRIVATE KEY')
+    ('-----BEGIN RSA PRIVATE KEY-----', '-----END RSA PRIVATE KEY-----')
+
+    '''
+
+    return ('-----BEGIN %s-----' % pem_marker,
+            '-----END %s-----' % pem_marker)
+
+def load_pem(contents, pem_marker):
+    '''Loads a PEM file.
+
+    @param contents: the contents of the file to interpret
+    @param pem_marker: the marker of the PEM content, such as 'RSA PRIVATE KEY'
+        when your file has '-----BEGIN RSA PRIVATE KEY-----' and
+        '-----END RSA PRIVATE KEY-----' markers.
+
+    @return the base64-decoded content between the start and end markers.
+
+    @raise ValueError: when the content is invalid, for example when the start
+        marker cannot be found.
+
+    '''
+
+    (pem_start, pem_end) = _markers(pem_marker)
+
+    pem_lines = []
+    in_pem_part = False
+
+    for line in contents.split('\n'):
+        line = line.strip()
+
+        # Skip empty lines
+        if not line:
+            continue
+
+        # Handle start marker
+        if line == pem_start:
+            if in_pem_part:
+                raise ValueError('Seen start marker "%s" twice' % pem_start)
+
+            in_pem_part = True
+            continue
+
+        # Skip stuff before first marker
+        if not in_pem_part:
+            continue
+
+        # Handle end marker
+        if in_pem_part and line == pem_end:
+            in_pem_part = False
+            break
+
+        # Load fields
+        if ':' in line:
+            continue
+
+        pem_lines.append(line)
+
+    # Do some sanity checks
+    if not pem_lines:
+        raise ValueError('No PEM start marker "%s" found' % pem_start)
+
+    if in_pem_part:
+        raise ValueError('No PEM end marker "%s" found' % pem_end)
+
+    # Base64-decode the contents
+    pem = ''.join(pem_lines)
+    return base64.decodestring(pem)
+
+def save_pem(contents, pem_marker):
+    '''Saves a PEM file.
+
+    @param contents: the contents to encode in PEM format
+    @param pem_marker: the marker of the PEM content, such as 'RSA PRIVATE KEY'
+        when your file has '-----BEGIN RSA PRIVATE KEY-----' and
+        '-----END RSA PRIVATE KEY-----' markers.
+
+    @return the base64-encoded content between the start and end markers.
+
+    '''
+
+    (pem_start, pem_end) = _markers(pem_marker)
+
+    b64 = base64.encodestring(contents).replace('\n', '')
+    pem_lines = [pem_start]
+    
+    for block_start in range(0, len(b64), 64):
+        block = b64[block_start:block_start + 64]
+        pem_lines.append(block)
+
+    pem_lines.append(pem_end)
+    pem_lines.append('')
+
+    return '\n'.join(pem_lines)
+