merge logic started

src/metadata.py

@@ -4,6 +4,7 @@ from ast import List
 from typing import Any, Union, Dict
 from dataclasses import dataclass
 from datetime import datetime
+import json
 
 
 @dataclass
@@ -21,12 +22,25 @@ class Metadata:
         self.status = status
         self.metadata = {}
 
-    # @staticmethod
     def merge(self: Metadata, right: Metadata, overwrite_left=True) -> Metadata:
-        # should return a merged version of the Metadata
-        # will work for archived() and enriched()
-        # what if 2 metadatas contain the same keys? only one can remain! : overwrite_left
-        pass
+        """
+        merges to Metadata instances, will overwrite according to overwrite_left flag
+        """
+        res = Metadata()
+        if overwrite_left:
+            res.status = right.status
+            res.metadata = dict(self.metadata)  # make a copy
+            for k, v in right.metadata.items():
+                print(type(v), type(self.get(k)))
+                # assert type(v) == type(self.get(k))
+                if type(v) not in [dict, list, set] or k not in res.metadata:
+                    res.set(k, v)
+                else:  # key conflict
+                    if type(v) in [dict, set]: res.set(k, self.get(k) | v)
+                    elif type(v) == list: res.set(k, self.get(k) + v)
+        else:  # invert and do same logic
+            return right.merge(self)
+        return res
 
     # TODO: setters?
     def set(self, key: str, val: Any) -> Metadata:
@@ -34,8 +48,10 @@ class Metadata:
         self.metadata[key] = val
         return self
 
-    def get(self, key: str, default: Any = None) -> Union[Metadata, str]:
+    def get(self, key: str, default: Any = None, create_if_missing=False) -> Union[Metadata, str]:
         # goes through metadata and returns the Metadata available
+        if create_if_missing and key not in self.metadata:
+            self.metadata[key] = default
         return self.metadata.get(key, default)
 
 # custom getter/setters
@@ -50,7 +66,11 @@ class Metadata:
         return url
 
     def get_media(self) -> List:
-        return self.get("media", [])
+        return self.get("media", [], create_if_missing=True)
+
+    def set_content(self, content: str) -> Metadata:
+        # the main textual content/information from a social media post, webpage, ...
+        return self.set("content", content)
 
     def set_title(self, title: str) -> Metadata:
         return self.set("title", title)
@@ -59,8 +79,10 @@ class Metadata:
         return self.set("title", title)
 
     def add_media(self, filename: str) -> Metadata:
+        # print(f"adding {filename} to {self.metadata.get('media')}")
+        # return self.set("media", self.get_media() + [filename])
         return self.get_media().append(filename)
 
     def as_json(self) -> str:
         # converts all metadata and data into JSON
-        pass
+        return json.dumps(self.metadata)