[enh] Initial Petalsearch Images support

Upstream example query:

  https://petalsearch.com/search?query=test&channel=image&ps=50&pn=1&region=de-de&ss_mode=off&ss_type=normal

Depending on locale it will internally use some/all results from other
engines. See:

  https://seirdy.one/posts/2021/03/10/search-engines-with-own-indexes/#general-indexing-search-engines

searx/engines/petal_images.py

@@ -0,0 +1,94 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""Petalsearch Images
+
+"""
+
+from json import loads
+from urllib.parse import urlencode
+from datetime import datetime
+
+from lxml import html
+
+from searx.utils import extract_text
+
+about = {
+    "website": 'https://petalsearch.com/',
+    "wikidata_id": 'Q104399280',
+    "official_api_documentation": False,
+    "use_official_api": False,
+    "require_api_key": False,
+    "results": 'JSON',
+}
+
+categories = ['images']
+paging = True
+time_range_support = False
+
+safesearch = True
+safesearch_table = {0: 'off', 1: 'moderate', 2: 'on'}
+
+base_url = 'https://petalsearch.com/'
+search_string = 'search?{query}&channel=image&ps=50&pn={page}&region={lang}&ss_mode={safesearch}&ss_type=normal'
+
+
+def request(query, params):
+
+    search_path = search_string.format(
+        query=urlencode({'query': query}),
+        page=params['pageno'],
+        lang=params['language'].lower(),
+        safesearch=safesearch_table[params['safesearch']],
+    )
+
+    params['url'] = base_url + search_path
+
+    return params
+
+
+def response(resp):
+    results = []
+
+    tree = html.fromstring(resp.text)
+    root = tree.findall('.//script[3]')
+
+    # Convert list to JSON
+    json_content = extract_text(root)
+
+    # Manipulate with JSON
+    data = loads(json_content)
+
+    for result in data['newImages']:
+        url = result['url']
+        title = result['title']
+        thumbnail_src = result['image']
+
+        pic_dict = result.get('extrainfo')
+
+        date_from_api = pic_dict.get('publish_time')
+        width = pic_dict.get('width')
+        height = pic_dict.get('height')
+        img_src = pic_dict.get('real_url')
+
+        # Continue if img_src is missing
+        if img_src is None or '':
+            continue
+
+        # Get and convert published date
+        if date_from_api is not None:
+            publishedDate = datetime.fromtimestamp(int(date_from_api))
+
+        # Append results
+        results.append(
+            {
+                'template': 'images.html',
+                'url': url,
+                'title': title,
+                'img_src': img_src,
+                'thumbnail_src': thumbnail_src,
+                'width': width,
+                'height': height,
+                'publishedDate': publishedDate,
+            }
+        )
+
+    return results

searx/settings.yml

@@ -1720,6 +1720,12 @@ engines:
       require_api_key: false
       results: HTML
 
+  - name: petalsearch images
+    engine: petal_images
+    shortcut: ptsi
+    disabled: true
+    timeout: 3.0
+
   - name: petalsearch news
     shortcut: ptsn
     categories: news