Allow images to be downloaded from URLs (#5214)

Co-authored-by: guillempages <guillempages@users.noreply.github.com>
Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

esphome/external_files.py

@@ -0,0 +1,75 @@
+from __future__ import annotations
+
+import logging
+from pathlib import Path
+import os
+from datetime import datetime
+import requests
+import esphome.config_validation as cv
+from esphome.core import CORE, TimePeriodSeconds
+
+_LOGGER = logging.getLogger(__name__)
+CODEOWNERS = ["@landonr"]
+
+NETWORK_TIMEOUT = 30
+
+IF_MODIFIED_SINCE = "If-Modified-Since"
+CACHE_CONTROL = "Cache-Control"
+CACHE_CONTROL_MAX_AGE = "max-age="
+CONTENT_DISPOSITION = "content-disposition"
+TEMP_DIR = "temp"
+
+
+def has_remote_file_changed(url, local_file_path):
+    if os.path.exists(local_file_path):
+        _LOGGER.debug("has_remote_file_changed: File exists at %s", local_file_path)
+        try:
+            local_modification_time = os.path.getmtime(local_file_path)
+            local_modification_time_str = datetime.utcfromtimestamp(
+                local_modification_time
+            ).strftime("%a, %d %b %Y %H:%M:%S GMT")
+
+            headers = {
+                IF_MODIFIED_SINCE: local_modification_time_str,
+                CACHE_CONTROL: CACHE_CONTROL_MAX_AGE + "3600",
+            }
+            response = requests.head(url, headers=headers, timeout=NETWORK_TIMEOUT)
+
+            _LOGGER.debug(
+                "has_remote_file_changed: File %s, Local modified %s, response code %d",
+                local_file_path,
+                local_modification_time_str,
+                response.status_code,
+            )
+
+            if response.status_code == 304:
+                _LOGGER.debug(
+                    "has_remote_file_changed: File not modified since %s",
+                    local_modification_time_str,
+                )
+                return False
+            _LOGGER.debug("has_remote_file_changed: File modified")
+            return True
+        except requests.exceptions.RequestException as e:
+            raise cv.Invalid(
+                f"Could not check if {url} has changed, please check if file exists "
+                f"({e})"
+            )
+
+    _LOGGER.debug("has_remote_file_changed: File doesn't exists at %s", local_file_path)
+    return True
+
+
+def is_file_recent(file_path: str, refresh: TimePeriodSeconds) -> bool:
+    if os.path.exists(file_path):
+        creation_time = os.path.getctime(file_path)
+        current_time = datetime.now().timestamp()
+        return current_time - creation_time <= refresh.total_seconds
+    return False
+
+
+def compute_local_file_dir(domain: str) -> Path:
+    base_directory = Path(CORE.data_dir) / domain
+    base_directory.mkdir(parents=True, exist_ok=True)
+
+    return base_directory