Add functions to efficiently serialize records

[idem-s1n]

When serializing records, looping through all the columns is time consuming on big databases.

Therefore, I have added a function to extract only the fields defined in a record then map them to the right column.

[idem-s1n]

Hi @Schamper

Thank you for requesting a review for this PR.
Is there a reason why it is still pending ?

[Schamper]

Apologies @idem-s1n. I meant to read a bit into ESEDB again before starting the review so I could provide better suggestions, however I hadn't gotten around to that yet (conferences, time off, other work). Specifically, I wanted to propose a method that reduces the amount of code duplication with the other (regular) way of retrieving a column. I could've just commented that, so please forgive me for only doing that now 😄.

Would it work/get sufficient performance if you just did the column lookup and then simply call .get(column) with that column? That should only add a few lines per fixed/variable/tagged, instead of duplicating most of the parsing code.

[idem-s1n]

Thanks @Schamper for the feedback.

I did some tests with a call to .get(column), there is a slight loss of performance. However, calling ._parse_value(column) gives better results.

Therefore, I have updated the serialize() function in order to reduce duplication of the parsing code. Changes were pushed on our main branch.

[codecov]

Codecov Report

Merging #24 (974543b) into main (f477082) will increase coverage by 0.02%.
The diff coverage is 82.35%.

@@            Coverage Diff             @@
##             main      #24      +/-   ##
==========================================
+ Coverage   79.12%   79.15%   +0.02%     
==========================================
  Files          15       15              
  Lines        1255     1271      +16     
==========================================
+ Hits          993     1006      +13     
- Misses        262      265       +3     

Flag	Coverage Δ
unittests	79.15% <82.35%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
dissect/esedb/record.py	84.26% <82.35%> (-0.20%)	⬇️

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[Schamper]

I don't have permission to push to your branch, so could you please apply the following changes. It adds a unit test and fixes a range error for the column IDs. It also corrects the linting issue.

diff --git a/dissect/esedb/record.py b/dissect/esedb/record.py
index 4d2d95d..0cbe4c2 100644
--- a/dissect/esedb/record.py
+++ b/dissect/esedb/record.py
@@ -4,7 +4,7 @@ import functools
 import struct
 from binascii import hexlify
 from functools import lru_cache
-from typing import TYPE_CHECKING, Any, Optional, Iterator
+from typing import TYPE_CHECKING, Any, Iterator, Optional

 from dissect.util.xmemoryview import xmemoryview

@@ -128,7 +128,9 @@ class RecordData:
             if num_variable > 0 and len(self.data) >= 4 + (num_variable * 2):
                 # Parse the variable offsets already, if we have them
                 # There can only be 128 at most, so this shouldn't be an expensive operation
-                self._variable_offsets = struct.unpack("<%dH" % num_variable, self.data[self._variable_offset_start : self._variable_data_start])
+                self._variable_offsets = struct.unpack(
+                    "<%dH" % num_variable, self.data[self._variable_offset_start : self._variable_data_start]
+                )

             self._tagged_data_start = self._variable_data_start
             if self._variable_offsets:
@@ -190,10 +192,10 @@ class RecordData:

         def _iter_column_id() -> Iterator[Column]:
             # Fixed
-            yield from range(1, self._last_fixed_id)
-
+            yield from range(1, self._last_fixed_id + 1)
+
             # Variable
-            yield from range(128, self._last_variable_id)
+            yield from range(128, self._last_variable_id + 1)

             # Tagged
             for idx in range(self._tagged_data_count):
diff --git a/tests/test_record.py b/tests/test_record.py
new file mode 100644
index 0000000..afea747
--- /dev/null
+++ b/tests/test_record.py
@@ -0,0 +1,40 @@
+from typing import BinaryIO
+
+from dissect.esedb.esedb import EseDB
+
+
+def test_as_dict(basic_db: BinaryIO):
+    db = EseDB(basic_db)
+    table = db.table("basic")
+
+    records = list(table.records())
+    assert len(records) == 2
+
+    assert [r.as_dict() for r in records] == [
+        {
+            "Id": 1,
+            "Bit": False,
+            "UnsignedByte": 213,
+            "Short": -1337,
+            "Long": -13371337,
+            "Currency": 1337133713371337,
+            "IEEESingle": 1.0,
+            "IEEEDouble": 13371337.13371337,
+            "DateTime": 4675210852477960192,
+            "UnsignedLong": 13371337,
+            "LongLong": -13371337,
+            "GUID": "3f360af1-6766-46dc-9af2-0dacf295c2a1",
+            "UnsignedShort": 1337,
+        },
+        {
+            "Id": 2,
+            "Bit": True,
+            "UnsignedByte": 255,
+            "Short": 1339,
+            "Long": 13391339,
+            "Currency": -1339133913391339,
+            "IEEESingle": -2.0,
+            "IEEEDouble": -13391339.13391339,
+            "DateTime": -4537072128574357504,
+        },
+    ]

I'll also kick the CLA bot.

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[idem-s1n]

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[idem-s1n]

@Schamper Is it possible to plan a new version release so these changes are included in the pip package ?

[Schamper]

@Schamper Is it possible to plan a new version release so these changes are included in the pip package ?

I believe we have a new release planned for the end of next week/beginning of the week after!