[proxy] make package auto-installation work

15 files changed, 504 insertions, 25 deletions

diff --git a/setup.cfg b/setup.cfg
index 16dc04e..a2279f9 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -52,7 +52,7 @@ setup = setuptools_scm; babel
 
 builder =
 server = flask
-haketilo = mitmproxy; beautifulsoup4[html5lib]
+haketilo = flask; itsdangerous; mitmproxy; beautifulsoup4[html5lib]
 
 SPDX = reuse
 all = reuse; flask; mitmproxy; beautifulsoup4
diff --git a/src/hydrilla/locales/en_US/LC_MESSAGES/messages.po b/src/hydrilla/locales/en_US/LC_MESSAGES/messages.po
index ff2299c..4807509 100644
--- a/src/hydrilla/locales/en_US/LC_MESSAGES/messages.po
+++ b/src/hydrilla/locales/en_US/LC_MESSAGES/messages.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: hydrilla 2.0\n"
 "Report-Msgid-Bugs-To: koszko@koszko.org\n"
-"POT-Creation-Date: 2022-09-05 13:54+0200\n"
+"POT-Creation-Date: 2022-09-08 17:52+0200\n"
 "PO-Revision-Date: 2022-02-12 00:00+0000\n"
 "Last-Translator: Wojtek Kosior <koszko@koszko.org>\n"
 "Language: en_US\n"
@@ -184,13 +184,13 @@ msgstr "Data directory for Haketilo to use."
 msgid "cli_opt.haketilo.version"
 msgstr "Print version information and exit"
 
-#: src/hydrilla/proxy/addon.py:109
+#: src/hydrilla/proxy/addon.py:110
 msgid "haketilo_dir_already_configured"
 msgstr ""
 "Attempt was made to configure Haketilo Mitmproxy addon with data "
 "directory path but it has already been configured."
 
-#: src/hydrilla/proxy/addon.py:164
+#: src/hydrilla/proxy/addon.py:166
 msgid "err.proxy.unknown_error_{}_try_again"
 msgstr ""
 "Haketilo experienced an error. Try again.\n"
@@ -389,7 +389,7 @@ msgstr "Package view"
 msgid "web_ui.items.single.package.heading.name_{}"
 msgstr "Packages named '{}'"
 
-#: src/hydrilla/proxy/web_ui/templates/items/package_view.html.jinja:39
+#: src/hydrilla/proxy/web_ui/templates/items/package_view.html.jinja:41
 msgid "web_ui.items.single.package.version_list_heading"
 msgstr "Available versions"
 
@@ -515,6 +515,30 @@ msgstr "Available packages"
 msgid "web_ui.packages.enabled_version_{}"
 msgstr "enabled version {}"
 
+#: src/hydrilla/proxy/web_ui/templates/prompts/auto_install_error.html.jinja:24
+msgid "web_ui.prompts.auto_install_error.title"
+msgstr "Installation failure"
+
+#: src/hydrilla/proxy/web_ui/templates/prompts/auto_install_error.html.jinja:41
+msgid "web_ui.prompts.auto_install_error.heading"
+msgstr "Installation failure"
+
+#: src/hydrilla/proxy/web_ui/templates/prompts/auto_install_error.html.jinja:46
+msgid "web_ui.prompts.auto_install_error.package_{}_failed_to_install"
+msgstr ""
+"Automatically activated package '{}' failed to install because Haketilo "
+"couldn't fetch package files from its repository server. Please verify "
+"that you do have network connection and try again. You can also choose to"
+" permanently disable the package."
+
+#: src/hydrilla/proxy/web_ui/templates/prompts/auto_install_error.html.jinja:52
+msgid "web_ui.prompts.auto_install_error.disable_button"
+msgstr "Disable"
+
+#: src/hydrilla/proxy/web_ui/templates/prompts/auto_install_error.html.jinja:57
+msgid "web_ui.prompts.auto_install_error.retry_button"
+msgstr "Retry installation"
+
 #: src/hydrilla/proxy/web_ui/templates/repos/add.html.jinja:23
 msgid "web_ui.repos.add.title"
 msgstr "New repository"
diff --git a/src/hydrilla/proxy/addon.py b/src/hydrilla/proxy/addon.py
index c7fae7e..b9c4159 100644
--- a/src/hydrilla/proxy/addon.py
+++ b/src/hydrilla/proxy/addon.py
@@ -40,6 +40,7 @@ import traceback as tb
 from threading import Lock
 from pathlib import Path
 from contextlib import contextmanager
+from urllib.parse import urlparse
 
 from mitmproxy import tls, http, addonmanager, ctx
 from mitmproxy.script import concurrent
@@ -184,6 +185,14 @@ class HaketiloAddon:
         available at this point, so the handler effectively does nothing.
         """
         with self.http_safe_event_handling(flow):
+            referrer = flow.request.headers.get('referer')
+            if referrer is not None:
+                if urlparse(referrer).netloc == 'hkt.mitm.it' and \
+                   urlparse(flow.request.url).netloc != 'hkt.mitm.it':
+                    # Do not reveal to the site that Haketilo meta-site was
+                    # visited before.
+                    flow.request.headers.pop('referer', None)
+
             policy = self.try_get_policy(flow)
 
             if policy is not None:
diff --git a/src/hydrilla/proxy/policies/payload.py b/src/hydrilla/proxy/policies/payload.py
index e64653d..a063c7c 100644
--- a/src/hydrilla/proxy/policies/payload.py
+++ b/src/hydrilla/proxy/policies/payload.py
@@ -35,8 +35,12 @@ import dataclasses as dc
 import typing as t
 import re
 
+from urllib.parse import urlencode
+
+from itsdangerous.url_safe import URLSafeSerializer
 import bs4 # type: ignore
 
+from ...exceptions import HaketiloException
 from ...url_patterns import ParsedUrl
 from .. import csp
 from .. import state
@@ -65,7 +69,7 @@ class PayloadAwarePolicyFactory(base.PolicyFactory):
     @property
     def payload_ref(self) -> state.PayloadRef:
         """...."""
-        return self.payload_key.payload_ref
+        return self.payload_key.ref
 
     def __lt__(self, other: base.PolicyFactory) -> bool:
         """...."""
@@ -171,7 +175,7 @@ class PayloadInjectPolicy(PayloadAwarePolicy):
     def _script_urls(self, url: ParsedUrl) -> t.Iterable[str]:
         """...."""
         base_url = self.assets_base_url(url)
-        payload_ref = self.payload_data.payload_ref
+        payload_ref = self.payload_data.ref
 
         for path in payload_ref.get_script_paths():
             yield base_url + '/'.join(('static', *path))
@@ -261,10 +265,47 @@ class PayloadInjectPolicy(PayloadAwarePolicy):
             )
 
 
+class _PayloadHasProblemsError(HaketiloException):
+    pass
+
 class AutoPayloadInjectPolicy(PayloadInjectPolicy):
     """...."""
     priority: t.ClassVar[base.PolicyPriority] = base.PolicyPriority._ONE
 
+    def consume_response(self, response_info: http_messages.ResponseInfo) \
+        -> http_messages.ProducedResponse:
+        try:
+            if self.payload_data.ref.has_problems():
+                raise _PayloadHasProblemsError()
+
+            self.payload_data.ref.ensure_items_installed()
+
+            return super().consume_response(response_info)
+        except (state.RepoCommunicationError, state.FileInstallationError,
+                _PayloadHasProblemsError) as ex:
+            params = {
+                'next_url':   response_info.url.orig_url,
+                'payload_id': self.payload_data.ref.id
+            }
+
+            if isinstance(ex, state.FileInstallationError):
+                params['repo_id']     = ex.repo_id
+                params['file_sha256'] = ex.sha256
+
+            serializer = URLSafeSerializer(
+                self.payload_data.global_secret,
+                salt = 'auto_install_error'
+            )
+            query = urlencode({'details': serializer.dumps(params)})
+            redirect_url = 'https://hkt.mitm.it/auto_install_error?' + query
+            msg = 'Error occured when installing payload. Redirecting.'
+
+            return http_messages.ProducedResponse(
+                status_code = 303,
+                headers     = [(b'Location', redirect_url.encode())],
+                body        = msg.encode()
+            )
+
 
 @dc.dataclass(frozen=True)
 class PayloadSuggestPolicy(PayloadAwarePolicy):
diff --git a/src/hydrilla/proxy/policies/payload_resource.py b/src/hydrilla/proxy/policies/payload_resource.py
index 3aacea0..f50f574 100644
--- a/src/hydrilla/proxy/policies/payload_resource.py
+++ b/src/hydrilla/proxy/policies/payload_resource.py
@@ -77,7 +77,7 @@ class PayloadResourcePolicy(PayloadAwarePolicy):
         -> http_messages.ProducedResponse:
         """...."""
         try:
-            file_data = self.payload_data.payload_ref.get_file_data(path)
+            file_data = self.payload_data.ref.get_file_data(path)
         except state.MissingItemError:
             return resource_blocked_response
 
diff --git a/src/hydrilla/proxy/state.py b/src/hydrilla/proxy/state.py
index 03b6291..491a865 100644
--- a/src/hydrilla/proxy/state.py
+++ b/src/hydrilla/proxy/state.py
@@ -337,7 +337,7 @@ class ResourceVersionStore(Store[ResourceVersionRef]):
 @dc.dataclass(frozen=True)
 class PayloadKey:
     """...."""
-    payload_ref: 'PayloadRef'
+    ref: 'PayloadRef'
 
     mapping_identifier: str
 
@@ -348,13 +348,22 @@ class PayloadKey:
 @dc.dataclass(frozen=True)
 class PayloadData:
     """...."""
-    payload_ref: 'PayloadRef'
+    ref: 'PayloadRef'
 
     explicitly_enabled:    bool
     unique_token:          str
     pattern_path_segments: tuple[str, ...]
     eval_allowed:          bool
     cors_bypass_allowed:   bool
+    global_secret:         bytes
+
+@dc.dataclass(frozen=True)
+class PayloadDisplayInfo:
+    ref: 'PayloadRef'
+
+    mapping_info: MappingVersionDisplayInfo
+    pattern:      str
+    has_problems: bool
 
 @dc.dataclass(frozen=True)
 class FileData:
@@ -371,7 +380,15 @@ class PayloadRef(Ref):
         ...
 
     @abstractmethod
-    def get_mapping(self) -> MappingVersionRef:
+    def has_problems(self) -> bool:
+        ...
+
+    @abstractmethod
+    def get_display_info(self) -> PayloadDisplayInfo:
+        ...
+
+    @abstractmethod
+    def ensure_items_installed(self) -> None:
         """...."""
         ...
 
@@ -387,6 +404,9 @@ class PayloadRef(Ref):
         """...."""
         ...
 
+class PayloadStore(Store[PayloadRef]):
+    pass
+
 
 class MappingUseMode(Enum):
     """
@@ -449,8 +469,11 @@ class HaketiloState(ABC):
         ...
 
     @abstractmethod
-    def get_payload(self, payload_id: str) -> PayloadRef:
-        """...."""
+    def payload_store(self) -> PayloadStore:
+        ...
+
+    @abstractmethod
+    def get_secret(self) -> bytes:
         ...
 
     @abstractmethod
diff --git a/src/hydrilla/proxy/state_impl/_operations/prune_orphans.py b/src/hydrilla/proxy/state_impl/_operations/prune_orphans.py
index f4ebd52..5a3f4f0 100644
--- a/src/hydrilla/proxy/state_impl/_operations/prune_orphans.py
+++ b/src/hydrilla/proxy/state_impl/_operations/prune_orphans.py
@@ -102,6 +102,30 @@ WHERE
         file_id IN removed_files;
 '''
 
+_forget_files_data_sql = '''
+WITH forgotten_files AS (
+        SELECT
+                f.file_id
+        FROM
+                          files         AS f
+                     JOIN file_uses     AS fu
+                        USING (file_id)
+                LEFT JOIN item_versions AS iv
+                        ON (fu.item_version_id = iv.item_version_id AND
+                            iv.installed = 'I')
+        GROUP BY
+                f.file_id
+        HAVING
+                COUNT(iv.item_version_id) = 0
+)
+UPDATE
+        files
+SET
+        data = NULL
+WHERE
+        file_id IN forgotten_files;
+'''
+
 _remove_repo_iterations_sql = '''
 WITH removed_iterations AS (
         SELECT
@@ -141,5 +165,6 @@ def prune_orphans(cursor: sqlite3.Cursor) -> None:
         cursor.execute(sql)
     cursor.execute(_remove_items_sql)
     cursor.execute(_remove_files_sql)
+    cursor.execute(_forget_files_data_sql)
     cursor.execute(_remove_repo_iterations_sql)
     cursor.execute(_remove_repos_sql)
diff --git a/src/hydrilla/proxy/state_impl/base.py b/src/hydrilla/proxy/state_impl/base.py
index 82b8734..0559a42 100644
--- a/src/hydrilla/proxy/state_impl/base.py
+++ b/src/hydrilla/proxy/state_impl/base.py
@@ -35,6 +35,7 @@ from __future__ import annotations
 
 import sqlite3
 import threading
+import secrets
 import dataclasses as dc
 import typing as t
 
@@ -143,6 +144,8 @@ class HaketiloStateWithFields(st.HaketiloState):
 
     #settings:       st.HaketiloGlobalSettings
 
+    secret: bytes = dc.field(default_factory=(lambda: secrets.token_bytes(16)))
+
     policy_tree:   PolicyTree   = PolicyTree()
     payloads_data: PayloadsData = dc.field(default_factory=dict)
 
diff --git a/src/hydrilla/proxy/state_impl/concrete_state.py b/src/hydrilla/proxy/state_impl/concrete_state.py
index 4781baa..8bd25a9 100644
--- a/src/hydrilla/proxy/state_impl/concrete_state.py
+++ b/src/hydrilla/proxy/state_impl/concrete_state.py
@@ -158,12 +158,14 @@ class ConcreteHaketiloState(base.HaketiloStateWithFields):
             _operations.pull_missing_files(cursor)
 
     def rebuild_structures(self) -> None:
-        with self.cursor(transaction=True) as cursor:
+        with self.cursor() as cursor:
             cursor.execute(
                 '''
                 SELECT
-                        p.payload_id, p.pattern, p.eval_allowed,
-                                p.cors_bypass_allowed,
+                        p.payload_id,
+                        p.pattern,
+                        p.eval_allowed,
+                        p.cors_bypass_allowed,
                         ms.enabled,
                         i.identifier
                 FROM
@@ -175,7 +177,7 @@ class ConcreteHaketiloState(base.HaketiloStateWithFields):
                 '''
             )
 
-        rows = cursor.fetchall()
+            rows = cursor.fetchall()
 
         new_policy_tree = base.PolicyTree()
 
@@ -214,12 +216,13 @@ class ConcreteHaketiloState(base.HaketiloStateWithFields):
                 pattern_path_segments = parsed_pattern.path_segments
 
             payload_data = st.PayloadData(
-                payload_ref           = payload_ref,
+                ref                   = payload_ref,
                 explicitly_enabled    = enabled_status == 'E',
                 unique_token          = token,
                 pattern_path_segments = pattern_path_segments,
                 eval_allowed          = eval_allowed,
-                cors_bypass_allowed   = cors_bypass_allowed
+                cors_bypass_allowed   = cors_bypass_allowed,
+                global_secret         = self.secret
             )
 
             new_payloads_data[payload_ref] = payload_data
@@ -245,8 +248,11 @@ class ConcreteHaketiloState(base.HaketiloStateWithFields):
     def resource_version_store(self) -> st.ResourceVersionStore:
         return items.ConcreteResourceVersionStore(self)
 
-    def get_payload(self, payload_id: str) -> st.PayloadRef:
-        raise NotImplementedError()
+    def payload_store(self) -> st.PayloadStore:
+        return payloads.ConcretePayloadStore(self)
+
+    def get_secret(self) -> bytes:
+        return self.secret
 
     def get_settings(self) -> st.HaketiloGlobalSettings:
         return st.HaketiloGlobalSettings(
diff --git a/src/hydrilla/proxy/state_impl/items.py b/src/hydrilla/proxy/state_impl/items.py
index 5f2f274..3ba8f80 100644
--- a/src/hydrilla/proxy/state_impl/items.py
+++ b/src/hydrilla/proxy/state_impl/items.py
@@ -232,7 +232,7 @@ class ConcreteMappingRef(st.MappingRef):
                     new_frozen_status == old_frozen_status):
                     return
             else:
-                if old_active_version_id is None:
+                if old_active_version_id is None and old_enabled_status != 'D':
                     return
 
             self.state.recompute_dependencies([int(self.id)])
diff --git a/src/hydrilla/proxy/state_impl/payloads.py b/src/hydrilla/proxy/state_impl/payloads.py
index 2bee11f..e622e52 100644
--- a/src/hydrilla/proxy/state_impl/payloads.py
+++ b/src/hydrilla/proxy/state_impl/payloads.py
@@ -31,11 +31,14 @@ This module provides an interface to interact with payloads inside Haketilo.
 # Enable using with Python 3.7.
 from __future__ import annotations
 
+import sqlite3
 import dataclasses as dc
 import typing as t
 
+from ... import item_infos
 from .. import state as st
 from . import base
+from . import items
 
 
 @dc.dataclass(frozen=True, unsafe_hash=True)
@@ -48,8 +51,163 @@ class ConcretePayloadRef(st.PayloadRef):
         except KeyError:
             raise st.MissingItemError()
 
-    def get_mapping(self) -> st.MappingVersionRef:
-        raise NotImplementedError()
+    def has_problems(self) -> bool:
+        with self.state.cursor(transaction=True) as cursor:
+            cursor.execute(
+                '''
+                SELECT
+                        iv.installed == 'F'
+                FROM
+                             payloads      AS p
+                        JOIN item_versions AS iv
+                                ON p.mapping_item_id = iv.item_version_id
+                WHERE
+                        p.payload_id = ?;
+                ''',
+                (self.id,)
+            )
+
+            rows = cursor.fetchall()
+
+            if rows == []:
+                raise st.MissingItemError()
+
+            (mapping_install_failed,), = rows
+            if mapping_install_failed:
+                return True
+
+            cursor.execute(
+                '''
+                SELECT
+                        COUNT(*) > 0
+                FROM
+                             payloads                    AS p
+                        JOIN resolved_depended_resources AS rdd
+                                USING (payload_id)
+                        JOIN item_versions AS iv
+                                ON rdd.resource_item_id = iv.item_version_id
+                WHERE
+                        p.payload_id = ? AND iv.installed = 'F';
+                ''',
+                (self.id,)
+            )
+
+            (resource_install_failed,), = cursor.fetchall()
+            if resource_install_failed:
+                return True
+
+        return False
+
+    def get_display_info(self) -> st.PayloadDisplayInfo:
+        with self.state.cursor() as cursor:
+            cursor.execute(
+                '''
+                SELECT
+                        p.pattern,
+                        ive.item_version_id,
+                        ive.definition,
+                        ive.repo,
+                        ive.repo_iteration,
+                        ive.installed,
+                        ive.active,
+                        ive.is_orphan,
+                        ive.is_local
+                FROM
+                             payloads            AS p
+                        JOIN item_versions_extra AS ive
+                                ON p.mapping_item_id = ive.item_version_id
+                WHERE
+                        p.payload_id = ?;
+                ''',
+                (self.id,)
+            )
+
+            rows = cursor.fetchall()
+
+            if rows == []:
+                raise st.MissingItemError()
+
+            (pattern_str, mapping_version_id, definition, repo, repo_iteration,
+             installed_status, active_status, is_orphan, is_local), = rows
+
+            has_problems = self.has_problems()
+
+        mapping_version_ref = items.ConcreteMappingVersionRef(
+            id = str(mapping_version_id),
+            state = self.state
+        )
+
+        mapping_version_info = item_infos.MappingInfo.load(
+            definition,
+            repo,
+            repo_iteration
+        )
+
+        mapping_version_display_info = st.MappingVersionDisplayInfo(
+            ref       = mapping_version_ref,
+            info      = mapping_version_info,
+            installed = st.InstalledStatus(installed_status),
+            active    = st.ActiveStatus(active_status),
+            is_orphan = is_orphan,
+            is_local  = is_local
+        )
+
+        return st.PayloadDisplayInfo(
+            ref          = self,
+            mapping_info = mapping_version_display_info,
+            pattern      = pattern_str,
+            has_problems = has_problems
+        )
+
+    def ensure_items_installed(self) -> None:
+        with self.state.cursor(transaction=True) as cursor:
+            cursor.execute(
+                'SELECT mapping_item_id FROM payloads WHERE payload_id = ?;',
+                (self.id,)
+            )
+
+            rows = cursor.fetchall()
+
+            if rows == []:
+                raise st.MissingItemError()
+
+            (mapping_version_id,), = rows
+
+            cursor.execute(
+                '''
+                UPDATE
+                        item_versions
+                SET
+                        installed = 'I'
+                WHERE
+                        item_version_id = ?;
+                ''',
+                (mapping_version_id,)
+            )
+
+            cursor.execute(
+                '''
+                WITH depended_resource_ids AS (
+                        SELECT
+                                rdd.resource_item_id
+                        FROM
+                                     payloads                    AS p
+                                JOIN resolved_depended_resources AS rdd
+                                        USING (payload_id)
+                        WHERE
+                                payload_id = ?
+                )
+                UPDATE
+                        item_versions
+                SET
+                        installed = 'I'
+                WHERE
+                        item_version_id IN depended_resource_ids;
+                ''',
+                (self.id,)
+            )
+
+            self.state.pull_missing_files()
 
     def get_script_paths(self) \
         -> t.Iterable[t.Sequence[str]]:
@@ -135,3 +293,11 @@ class ConcretePayloadRef(st.PayloadRef):
         (data, mime_type), = result
 
         return st.FileData(type=mime_type, name=file_name, contents=data)
+
+
+@dc.dataclass(frozen=True)
+class ConcretePayloadStore(st.PayloadStore):
+    state: base.HaketiloStateWithFields
+
+    def get(self, id: str) -> st.PayloadRef:
+        return ConcretePayloadRef(str(int(id)), self.state)
diff --git a/src/hydrilla/proxy/web_ui/items.py b/src/hydrilla/proxy/web_ui/items.py
index 1a56d7d..a7e497b 100644
--- a/src/hydrilla/proxy/web_ui/items.py
+++ b/src/hydrilla/proxy/web_ui/items.py
@@ -238,6 +238,12 @@ def alter_item_version(item_version_id: str, item_type: item_infos.ItemType) \
                 return show_item_version(item_version_id, item_type)
         else:
             raise ValueError()
+    except st.RepoCommunicationError:
+        return show_item_version(
+            item_version_id = item_version_id,
+            item_type       = item_type,
+            errors          = {'repo_communication_error': True}
+        )
     except st.FileInstallationError:
         return show_item_version(
             item_version_id = item_version_id,
diff --git a/src/hydrilla/proxy/web_ui/prompts.py b/src/hydrilla/proxy/web_ui/prompts.py
new file mode 100644
index 0000000..b546e47
--- /dev/null
+++ b/src/hydrilla/proxy/web_ui/prompts.py
@@ -0,0 +1,115 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# Proxy web UI pages that may be shown to the user without manual navigation to
+# Haketilo meta-site.
+#
+# This file is part of Hydrilla&Haketilo.
+#
+# Copyright (C) 2022 Wojtek Kosior
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+#
+# I, Wojtek Kosior, thereby promise not to sue for violation of this
+# file's license. Although I request that you do not make use this code
+# in a proprietary program, I am not going to enforce this in court.
+
+# Enable using with Python 3.7.
+from __future__ import annotations
+
+import typing as t
+
+from urllib.parse import urlencode
+
+from itsdangerous.url_safe import URLSafeSerializer
+import flask
+import werkzeug
+
+from .. import state as st
+from . import _app
+
+
+bp = flask.Blueprint('prompts', __package__)
+
+@bp.route('/auto_install_error', methods=['GET'])
+def auto_install_error_prompt() -> werkzeug.Response:
+    state = _app.get_haketilo_state()
+
+    serializer = URLSafeSerializer(
+        state.get_secret(),
+        salt = 'auto_install_error'
+    )
+
+    try:
+        details: t.Mapping[str, str] = \
+            serializer.loads(flask.request.args['details'])
+    except:
+        return flask.redirect(flask.url_for('home'))
+
+    try:
+        payload_ref = state.payload_store().get(details['payload_id'])
+
+        display_info = payload_ref.get_display_info()
+
+        html = flask.render_template(
+            'prompts/auto_install_error.html.jinja',
+            display_info = display_info,
+            next_url     = details['next_url']
+        )
+        return flask.make_response(html, 200)
+    except st.MissingItemError:
+        flask.abort(404)
+
+@bp.route('/auto_install_error', methods=['POST'])
+def auto_install_error_prompt_post() -> werkzeug.Response:
+    form_data = flask.request.form
+    action = form_data['action']
+
+    mapping_ver_id = str(int(form_data['mapping_ver_id']))
+    payload_id     = str(int(form_data['payload_id']))
+    next_url       = form_data['next_url']
+
+    state = _app.get_haketilo_state()
+
+    try:
+        mapping_ver_store = state.mapping_version_store()
+        mapping_ver_ref = mapping_ver_store.get(mapping_ver_id)
+
+        payload_store = _app.get_haketilo_state().payload_store()
+        payload_ref = payload_store.get(payload_id)
+
+        if action == 'disable_mapping':
+            mapping_ver_ref.update_mapping_status(st.EnabledStatus.DISABLED)
+        elif action == 'retry_install':
+            payload_ref.ensure_items_installed()
+        else:
+            raise ValueError()
+    except (st.RepoCommunicationError, st.FileInstallationError):
+        params = {'payload_id': payload_id, 'next_url': next_url}
+
+        serializer = URLSafeSerializer(
+            state.get_secret(),
+            salt = 'auto_install_error'
+        )
+        query = urlencode({'details': params})
+        redirect_url = flask.url_for(
+            '.auto_install_error_prompt',
+            details = serializer.dumps(params)
+        )
+
+        return flask.redirect(redirect_url)
+    except st.MissingItemError:
+        flask.abort(404)
+
+    return flask.redirect(next_url)
diff --git a/src/hydrilla/proxy/web_ui/root.py b/src/hydrilla/proxy/web_ui/root.py
index eac3be7..ff7c1f7 100644
--- a/src/hydrilla/proxy/web_ui/root.py
+++ b/src/hydrilla/proxy/web_ui/root.py
@@ -46,6 +46,7 @@ from .. import state as st
 from .. import http_messages
 from . import repos
 from . import items
+from . import prompts
 from . import _app
 
 
@@ -91,7 +92,7 @@ class WebUIAppImpl(_app.WebUIApp):
 
         self.before_request(authenticate_by_referrer)
 
-        for blueprint in [repos.bp, items.bp]:
+        for blueprint in [repos.bp, items.bp, prompts.bp]:
             self.register_blueprint(blueprint)
 
 # Flask app is not thread-safe and has to be accompanied by an ugly lock. This
diff --git a/src/hydrilla/proxy/web_ui/templates/prompts/auto_install_error.html.jinja b/src/hydrilla/proxy/web_ui/templates/prompts/auto_install_error.html.jinja
new file mode 100644
index 0000000..01f5c19
--- /dev/null
+++ b/src/hydrilla/proxy/web_ui/templates/prompts/auto_install_error.html.jinja
@@ -0,0 +1,60 @@
+{#
+SPDX-License-Identifier: GPL-3.0-or-later OR CC-BY-SA-4.0
+
+Proxy web UI page that informs about failure of automatic package installation.
+
+This file is part of Hydrilla&Haketilo.
+
+Copyright (C) 2022 Wojtek Kosior
+
+Dual licensed under
+* GNU General Public License v3.0 or later and
+* Creative Commons Attribution Share Alike 4.0 International.
+
+You can choose to use either of these licenses or both.
+
+
+I, Wojtek Kosior, thereby promise not to sue for violation of this
+file's licenses. Although I request that you do not make use this code
+in a proprietary work, I am not going to enforce this in court.
+#}
+{% extends "base.html.jinja" %}
+
+{% block title %}
+  {{ _('web_ui.prompts.auto_install_error.title') }}
+{% endblock %}
+
+{% macro button_form(action, button_class, button_text) %}
+  <form class="flex-row" method="POST">
+    <input name="next_url" value="{{ next_url }}" type="hidden">
+    <input name="payload_id" value="{{ display_info.ref.id }}" type="hidden">
+    {% set mapping_ver_id = display_info.mapping_info.ref.id %}
+    <input name="mapping_ver_id" value="{{ mapping_ver_id }}" type="hidden">
+
+    <input name="action" value="{{ action }}" type="hidden">
+    <button class="{{ button_class }}">{{ button_text }}</button>
+  </form>
+{% endmacro %}
+
+{% block main %}
+  <h3>
+    {{ _('web_ui.prompts.auto_install_error.heading') }}
+  </h3>
+
+  <p>
+    {{
+      _('web_ui.prompts.auto_install_error.package_{}_failed_to_install')
+          .format(display_info.mapping_info.info.long_name)
+    }}
+  </p>
+
+  <div class="flex-row">
+    {% set but_text = _('web_ui.prompts.auto_install_error.disable_button') %}
+    {{ button_form('disable_mapping', 'red-button', but_text) }}
+
+    <div class="button-row-separator"></div>
+
+    {% set but_text = _('web_ui.prompts.auto_install_error.retry_button') %}
+    {{ button_form('retry_install', 'green-button', but_text) }}
+  </div>
+{% endblock %}