diff --git a/api/s18_sources.py b/api/s18_sources.py
index 2d489c0..d06a73a 100644
--- a/api/s18_sources.py
+++ b/api/s18_sources.py
@@ -98,3 +98,40 @@ def delete_source_cache(name: str, cs: ChangeSet) -> SqlChangeSet:
 
 def delete_source(name: str, cs: ChangeSet) -> ChangeSet:
     return execute_command(name, delete_source_cache(name, cs))
+
+
+class InpSource:
+    def __init__(self, line: str) -> None:
+        tokens = line.split()
+
+        num = len(tokens)
+        has_desc = tokens[-1].startswith(';')
+        num_without_desc = (num - 1) if has_desc else num
+
+        self.node = str(tokens[0])
+        self.s_type = float(tokens[1])
+        self.strength = float(tokens[2])
+        self.pattern = str(tokens[3]) if num_without_desc >= 4 else None
+
+
+def inp_in_source(section: list[str]) -> ChangeSet:
+    cs = ChangeSet()
+    for s in section:
+        # skip comment
+        if s.startswith(';'):
+            continue
+        obj = InpSource(s)
+        cs.append({'operation': API_ADD, 'type': 'source', 'node': obj.node, 's_type': obj.s_type, 'strength': obj.strength, 'pattern': obj.pattern})
+    return cs
+
+
+def inp_out_source(name: str) -> list[str]:
+    lines = []
+    objs = read_all(name, 'select * from sources')
+    for obj in objs:
+        node = obj['node']
+        s_type = obj['s_type']
+        strength = obj['strength']
+        pattern = obj['pattern'] if obj['pattern'] != None else ''
+        lines.append(f'{node} {s_type} {strength} {pattern}')
+    return lines