Add content digest util method

charon/utils/files.py

@@ -58,9 +58,30 @@ def read_sha1(file: str) -> str:
 
 
 def digest(file: str, hash_type=HashType.SHA1) -> str:
+    hash_obj = _hash_object(hash_type)
+
     # BUF_SIZE is totally arbitrary, change for your app!
     BUF_SIZE = 65536  # lets read stuff in 64kb chunks!
+    with open(file, "rb") as f:
+        while True:
+            data = f.read(BUF_SIZE)
+            if not data:
+                break
+            hash_obj.update(data)
+
+    return hash_obj.hexdigest()
 
+
+def digest_content(content: str, hash_type=HashType.SHA1) -> str:
+    """This function will caculate the hash value for the string content with the specified
+       hash type
+    """
+    hash_obj = _hash_object(hash_type)
+    hash_obj.update(content.encode('utf-8'))
+    return hash_obj.hexdigest()
+
+
+def _hash_object(hash_type: HashType):
     hash_obj = None
     if hash_type == HashType.SHA1:
         hash_obj = hashlib.sha1()
@@ -70,15 +91,7 @@ def digest(file: str, hash_type=HashType.SHA1) -> str:
         hash_obj = hashlib.md5()
     else:
         raise Exception("Error: Unknown hash type for digesting.")
-
-    with open(file, "rb") as f:
-        while True:
-            data = f.read(BUF_SIZE)
-            if not data:
-                break
-            hash_obj.update(data)
-
-    return hash_obj.hexdigest()
+    return hash_obj
 
 
 def write_manifest(paths: List[str], root: str, product_key: str) -> Tuple[str, str]:

tests/test_util.py

@@ -13,7 +13,7 @@
 See the License for the specific language governing permissions and
 limitations under the License.
 """
-from charon.utils.files import digest, read_sha1, HashType
+from charon.utils.files import digest, digest_content, read_sha1, HashType
 import os
 import unittest
 
@@ -29,6 +29,14 @@ def test_digest(self):
             digest(test_file, HashType.SHA256),
         )
 
+    def test_digest_content(self):
+        test_content = "test common content"
+        self.assertEqual("8c7b70f25fb88bc6a0372f70f6805132e90e2029", digest_content(test_content))
+        self.assertEqual(
+            "1a1c26da1f6830614ed0388bb30d9e849e05bba5de4031e2a2fa6b48032f5354",
+            digest_content(test_content, HashType.SHA256),
+        )
+
     def test_read_sha1(self):
         test_file = os.path.join(INPUTS, "commons-lang3.zip")
         # read the real sha1 hash