Add recoll engine (#2325)

recoll is a local search engine based on Xapian:
http://www.lesbonscomptes.com/recoll/

By itself recoll does not offer web or API access,
this can be achieved using recoll-webui:
https://framagit.org/medoc92/recollwebui.git

This engine uses a custom 'files' result template

set `base_url` to the location where recoll-webui can be reached
set `dl_prefix` to a location where the file hierarchy as indexed by recoll can be reached
set `search_dir` to the part of the indexed file hierarchy to be searched, use an empty string to search the entire search domain

8 files changed, 298 insertions, 6 deletions

diff --git a/docs/admin/engines.rst b/docs/admin/engines.rst
index 4d1872dfc..f1ac03699 100644
--- a/docs/admin/engines.rst
+++ b/docs/admin/engines.rst
@@ -1,14 +1,28 @@
-.. _engines generic:
-
 =======
 Engines
 =======
 
+Special Engine Settings
+=======================
+
 .. sidebar:: Further reading ..
 
    - :ref:`settings engine`
-   - :ref:`engine settings`
-   - :ref:`engine file`
+   - :ref:`engine settings` & :ref:`engine file`
+
+.. toctree::
+   :maxdepth: 1
+
+   engines/recoll.rst
+
+
+.. _engines generic:
+
+General Engine Settings
+=======================
+
+Explanation of the :ref:`general engine configuration` shown in the table
+:ref:`configured engines`.
 
 ============= =========== ==================== ============
 :ref:`engine settings`    :ref:`engine file`
@@ -30,8 +44,6 @@ Disabled      **D**
 Show errors   **DE**
 ============= =========== =================================
 
-Configuration defaults (at built time):
-
 .. _configured engines:
 
 .. jinja:: webapp
@@ -73,3 +85,4 @@ Configuration defaults (at built time):
         - {{(mod.display_error_messages and "y") or ""}}
 
      {% endfor %}
+
diff --git a/docs/admin/engines/recoll.rst b/docs/admin/engines/recoll.rst
new file mode 100644
index 000000000..cba2e81f7
--- /dev/null
+++ b/docs/admin/engines/recoll.rst
@@ -0,0 +1,50 @@
+.. _engine recoll:
+
+======
+Recoll
+======
+
+.. sidebar:: info
+
+   - `Recoll <https://www.lesbonscomptes.com/recoll/>`_
+   - `recoll-webui <https://framagit.org/medoc92/recollwebui.git>`_
+
+Recoll_ is a desktop full-text search tool based on Xapian. By itself Recoll_
+does not offer web or API access, this can be achieved using recoll-webui_
+
+
+
+Configuration
+=============
+
+You must configure the following settings:
+
+``base_url``:
+  Location where recoll-webui can be reached.
+
+``mount_prefix``:
+  Location where the file hierarchy is mounted on your *local* filesystem.
+
+``dl_prefix``:
+  Location where the file hierarchy as indexed by recoll can be reached.
+
+``search_dir``:
+  Part of the indexed file hierarchy to be search, if empty the full domain is
+  searched.
+
+
+Example
+=======
+
+Scenario:
+
+#. Recoll indexes a local filesystem mounted in ``/export/documents/reference``,
+#. the Recoll search inteface can be reached at https://recoll.example.org/ and
+#. the contents of this filesystem can be reached though https://download.example.org/reference
+
+.. code:: yaml
+
+   base_url: https://recoll.example.org/
+   mount_prefix: /export/documents
+   dl_prefix: https://download.example.org
+   search_dir: ''
diff --git a/docs/dev/engine_overview.rst b/docs/dev/engine_overview.rst
index 268995a45..5e3483fd7 100644
--- a/docs/dev/engine_overview.rst
+++ b/docs/dev/engine_overview.rst
@@ -18,6 +18,9 @@ engines.  Adapters are stored under the folder :origin:`searx/engines`.
    :depth: 3
    :backlinks: entry
 
+
+.. _general engine configuration:
+
 general engine configuration
 ============================
 
diff --git a/searx/engines/recoll.py b/searx/engines/recoll.py
new file mode 100644
index 000000000..5a956b8bf
--- /dev/null
+++ b/searx/engines/recoll.py
@@ -0,0 +1,104 @@
+"""
+ Recoll (local search engine)
+
+ @using-api   yes
+ @results     JSON
+ @stable      yes
+ @parse       url, content, size, abstract, author, mtype, subtype, time, \
+              filename, label, type, embedded
+"""
+
+from datetime import date, timedelta
+from json import loads
+from urllib.parse import urlencode, quote
+
+# engine dependent config
+time_range_support = True
+
+# parameters from settings.yml
+base_url = None
+search_dir = ''
+mount_prefix = None
+dl_prefix = None
+
+# embedded
+embedded_url = '<{ttype} controls height="166px" ' +\
+    'src="{url}" type="{mtype}"></{ttype}>'
+
+
+# helper functions
+def get_time_range(time_range):
+    sw = {
+        'day': 1,
+        'week': 7,
+        'month': 30,
+        'year': 365
+    }
+
+    offset = sw.get(time_range, 0)
+    if not offset:
+        return ''
+
+    return (date.today() - timedelta(days=offset)).isoformat()
+
+
+# do search-request
+def request(query, params):
+    search_after = get_time_range(params['time_range'])
+    search_url = base_url + 'json?{query}&highlight=0'
+    params['url'] = search_url.format(query=urlencode({
+        'query': query,
+        'after': search_after,
+        'dir': search_dir}))
+
+    return params
+
+
+# get response from search-request
+def response(resp):
+    results = []
+
+    response_json = loads(resp.text)
+
+    if not response_json:
+        return []
+
+    for result in response_json.get('results', []):
+        title = result['label']
+        url = result['url'].replace('file://' + mount_prefix, dl_prefix)
+        content = '{}'.format(result['snippet'])
+
+        # append result
+        item = {'url': url,
+                'title': title,
+                'content': content,
+                'template': 'files.html'}
+
+        if result['size']:
+            item['size'] = int(result['size'])
+
+        for parameter in ['filename', 'abstract', 'author', 'mtype', 'time']:
+            if result[parameter]:
+                item[parameter] = result[parameter]
+
+        # facilitate preview support for known mime types
+        if 'mtype' in result and '/' in result['mtype']:
+            (mtype, subtype) = result['mtype'].split('/')
+            item['mtype'] = mtype
+            item['subtype'] = subtype
+
+            if mtype in ['audio', 'video']:
+                item['embedded'] = embedded_url.format(
+                    ttype=mtype,
+                    url=quote(url.encode('utf8'), '/:'),
+                    mtype=result['mtype'])
+
+            if mtype in ['image'] and subtype in ['bmp', 'gif', 'jpeg', 'png']:
+                item['img_src'] = url
+
+        results.append(item)
+
+    if 'nres' in response_json:
+        results.append({'number_of_results': response_json['nres']})
+
+    return results
diff --git a/searx/settings.yml b/searx/settings.yml
index 8af1a17f1..33ae234d5 100644
--- a/searx/settings.yml
+++ b/searx/settings.yml
@@ -650,6 +650,28 @@ engines:
     shortcut : qws
     categories : social media
 
+#  - name: library
+#    engine: recoll
+#    shortcut: lib
+#    base_url: 'https://recoll.example.org/'
+#    search_dir: ''
+#    mount_prefix: /export
+#    dl_prefix: 'https://download.example.org'
+#    timeout: 30.0
+#    categories: files
+#    disabled: True
+
+#  - name: recoll library reference
+#    engine: recoll
+#    base_url: 'https://recoll.example.org/'
+#    search_dir: reference
+#    mount_prefix: /export
+#    dl_prefix: 'https://download.example.org'
+#    shortcut: libr
+#    timeout: 30.0
+#    categories: files
+#    disabled: True
+
   - name : reddit
     engine : reddit
     shortcut : re
diff --git a/searx/static/themes/oscar/less/logicodev/results.less b/searx/static/themes/oscar/less/logicodev/results.less
index 9926d6e53..33965fb33 100644
--- a/searx/static/themes/oscar/less/logicodev/results.less
+++ b/searx/static/themes/oscar/less/logicodev/results.less
@@ -51,6 +51,11 @@
     float: right;
 }
 
+.result-abstract {
+    margin-top: 0.5em;
+    margin-bottom: 0.8em;
+}
+
 .external-link {
     color: @dark-green;
     font-size: 12px;
@@ -124,6 +129,20 @@
     }
 }
 
+.result-metadata {
+    clear: both;
+    margin: 1em;
+
+    td {
+        padding-right: 1em;
+        color: @gray;
+    }
+
+    td:first-of-type {
+        color: @dark-gray;
+    }
+}
+
 // map formating of results
 .result-map {
     clear: both;
diff --git a/searx/templates/oscar/macros.html b/searx/templates/oscar/macros.html
index 57a90aaa2..2bc1e7805 100644
--- a/searx/templates/oscar/macros.html
+++ b/searx/templates/oscar/macros.html
@@ -47,6 +47,20 @@
     {%- endif -%}
 {%- endmacro %}
 
+<!-- Draw result footer without cache link -->
+{% macro result_footer_nocache(result) -%}
+    <div class="clearfix"></div>
+    <div class="pull-right">
+    {% for engine in result.engines %}
+        <span class="label label-default">{{ engine }}</span>
+    {% endfor %}
+    {% if proxify %}
+    <small>{{ result_link(proxify(result.url), icon('sort') + _('proxied'), "text-info") }}</small>
+    {% endif %}
+</div>
+<div class="external-link">{{ result.pretty_url }}</div>
+{%- endmacro %}
+
 <!-- Draw result footer -->
 {% macro result_footer_rtl(result, id) -%}
     <div class="clearfix"></div>{{- "" -}}
@@ -68,6 +82,18 @@
     {%- endif %}
 {%- endmacro %}
 
+<!-- Draw result footer without cache link -->
+{% macro result_footer_nocache_rtl(result) -%}
+    <div class="clearfix"></div>
+    {% for engine in result.engines %}
+        <span class="label label-default">{{ engine }}</span>
+    {% endfor %}
+    {% if proxify %}
+    <small>{{ result_link(proxify(result.url), icon('sort') + _('proxied'), "text-info") }}</small>
+    {% endif %}
+    <div class="external-link">{{ result.pretty_url }}</div>
+{%- endmacro %}
+
 {% macro preferences_item_header(info, label, rtl, id) -%}
     {% if rtl %}
     <div class="row form-group">
diff --git a/searx/templates/oscar/result_templates/files.html b/searx/templates/oscar/result_templates/files.html
new file mode 100644
index 000000000..5e3894e0a
--- /dev/null
+++ b/searx/templates/oscar/result_templates/files.html
@@ -0,0 +1,55 @@
+{% from 'oscar/macros.html' import result_header, result_sub_header, result_footer_nocache, result_footer_nocache_rtl, icon with context %}

+

+{{ result_header(result, favicons) }}

+{{ result_sub_header(result) }}

+

+{% if result.embedded %}

+    <small> &bull; <a class="text-info btn-collapse collapsed cursor-pointer media-loader disabled_if_nojs" data-toggle="collapse" data-target="#result-media-{{ index }}" data-btn-text-collapsed="{{ _('show media') }}" data-btn-text-not-collapsed="{{ _('hide media') }}">

+    {% if result.mtype == 'audio' %}{{ icon('music') }}

+    {% elif result.mtype == 'video' %} {{ icon('film') }}

+    {% endif %} {{ _('show media') }}</a></small>

+{% endif %}

+

+{% if result.embedded %}

+<div id="result-media-{{ index }}" class="collapse">

+   {{ result.embedded|safe }}

+</div>

+{% endif %}

+

+{% if result.abstract %}<p class="result-content result-abstract">{{ result.abstract|safe }}</p>{% endif %}

+

+{% if result.img_src %}

+<div class="container-fluid">

+    <div class="row">

+<img src="{{ image_proxify(result.img_src) }}" alt="{{ result.title|striptags }}" title="{{ result.title|striptags }}" style="width: auto; max-height: 60px; min-height: 60px;" class="col-xs-2 col-sm-4 col-md-4 result-content">

+{% if result.content %}<p class="result-content col-xs-8 col-sm-8 col-md-8">{{ result.content|safe }}</p>{% endif %}

+    </div>

+</div>

+{% else %}

+{% if result.content %}<p class="result-content">{{ result.content|safe }}</p>{% endif %}

+{% endif %}

+

+<table class="result-metadata result-content">

+{% if result.author %}<tr><td>{{ _('Author') }}</td><td>{{ result.author|safe }}</td></tr>{% endif %}

+

+{% if result.filename %}<tr><td>{{ _('Filename') }}</td><td>{{ result.filename|safe }}</td></tr>{% endif %}

+

+{% if result.size %}<tr><td>{{ _('Filesize') }}</td><td>

+        {% if result.size < 1024 %}{{ result.size }} {{ _('Bytes') }}

+        {% elif result.size < 1024*1024 %}{{ '{0:0.2f}'.format(result.size/1024) }} {{ _('kiB') }}

+        {% elif result.size < 1024*1024*1024 %}{{ '{0:0.2f}'.format(result.size/1024/1024) }} {{ _('MiB') }}

+        {% elif result.size < 1024*1024*1024*1024 %}{{ '{0:0.2f}'.format(result.size/1024/1024/1024) }} {{ _('GiB') }}

+        {% else %}{{ '{0:0.2f}'.format(result.size/1024/1024/1024/1024) }} {{ _('TiB') }}{% endif %}

+    </td></tr>

+{% endif %}

+

+{% if result.time %}<tr><td>{{ _('Date') }}</td><td>{{ result.time|safe }}</td></tr>{% endif %}

+

+{% if result.mtype %}<tr><td>{{ _('Type') }}</td><td>{{ result.mtype|safe }}/{{ result.subtype|safe }}</td></tr>{% endif %}

+</table>

+

+{% if rtl %}

+{{ result_footer_nocache_rtl(result) }}

+{% else %}

+{{ result_footer_nocache(result) }}

+{% endif %}