From 3a90ab0dbf5826bc7476971cd163c9a080d2fb2f Mon Sep 17 00:00:00 2001
From: Trygve Laugstøl <trygvis@inamo.no>
Date: Fri, 8 Mar 2019 22:30:36 +0100
Subject: Digikey: extracting http caching into its own class.

---
 src/ee/_utils.py                     | 38 +++++++++++++++++++++++++++++++++++-
 src/ee/digikey/__init__.py           | 19 +++++-------------
 src/ee/tools/digikey_search_parts.py |  2 +-
 3 files changed, 43 insertions(+), 16 deletions(-)

diff --git a/src/ee/_utils.py b/src/ee/_utils.py
index 29b039a..f917847 100644
--- a/src/ee/_utils.py
+++ b/src/ee/_utils.py
@@ -1,4 +1,5 @@
-from typing import List
+from pathlib import Path
+from typing import List, Optional
 
 
 def ensure_has_columns(df: "pandas.DataFrame", columns: List[str]):
@@ -40,3 +41,38 @@ def all(filters):
         return True
 
     return f
+
+
+class HttpCache(object):
+    def __init__(self, path: Path):
+        self.path = path
+
+    def lookup(self, key):
+        cache_path = self._make_path(key)
+
+        if cache_path.exists():
+            with open(str(cache_path), "r") as f:
+                return f.read()
+
+    def save(self, key, value):
+        cache_path = self._make_path(key)
+        cache_path.parent.mkdir(parents=True, exist_ok=True)
+
+        with cache_path.open("w") as f:
+            f.write(value)
+
+    def _make_path(self, key) -> Path:
+        return self.path / "{}.html".format(key)
+
+
+class EmptyHttpCache(object):
+    @staticmethod
+    def lookup(key):
+        return None
+
+    def save(self, key, value):
+        pass
+
+
+def maybe_cache(path: Optional[Path]) -> HttpCache:
+    return HttpCache(path) if path is not None else EmptyHttpCache()
diff --git a/src/ee/digikey/__init__.py b/src/ee/digikey/__init__.py
index 32308e5..6baae84 100644
--- a/src/ee/digikey/__init__.py
+++ b/src/ee/digikey/__init__.py
@@ -213,7 +213,7 @@ class DigikeyClient(object):
 
     def __init__(self, cache_dir: Path = None, on_download=None):
         self.on_download = on_download or self.__nop
-        self.cache_dir = cache_dir or Path()
+        self.cache = ee._utils.maybe_cache(cache_dir)
         self.driver: webdriver.Chrome = None
 
     def search(self, query: str, page_size=10) -> str:
@@ -231,14 +231,10 @@ class DigikeyClient(object):
             url = "https://www.digikey.com" + url
         url = url + ("" if not params else "?" + urllib.parse.urlencode(params))
 
-        cache_path: Optional[Path] = None
-        if self.cache_dir:
-            cache_path = self.cache_dir / "{}.html".format(cache_key)
-
-        if cache_path.exists():
+        cached = self.cache.lookup(cache_key)
+        if cached:
             self.on_download("Using cached {}".format(url))
-            with open(str(cache_path), "r") as f:
-                return f.read()
+            return cached
 
         self.on_download("Downloading {}".format(url))
 
@@ -249,12 +245,7 @@ class DigikeyClient(object):
         self.driver.get(url)
 
         src = self.driver.page_source
-        if cache_path:
-            cache_path.parent.mkdir(parents=True, exist_ok=True)
-
-            with open(str(cache_path), "w") as f:
-                f.write(src)
-            assert self.cache_dir.stat().st_size > 0
+        self.cache.save(cache_key, src)
 
         return src
 
diff --git a/src/ee/tools/digikey_search_parts.py b/src/ee/tools/digikey_search_parts.py
index 80393eb..07c3017 100644
--- a/src/ee/tools/digikey_search_parts.py
+++ b/src/ee/tools/digikey_search_parts.py
@@ -16,7 +16,7 @@ parser.add_argument("--out",
 
 args = parser.parse_args()
 
-cache_dir = ".ee/cache"
+cache_dir = ".ee/cache/digikey"
 force = True
 
 search_parts(Path(args.in_), Path(args.out), Path(cache_dir), force)
-- 
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