rz_user.py: rest__pw_reset()

2 files changed, 154 insertions, 0 deletions

diff --git a/src/server/rz_server.py b/src/server/rz_server.py
index 95463164..3077f723 100644
--- a/src/server/rz_server.py
+++ b/src/server/rz_server.py
@@ -221,6 +221,7 @@ def init_rest_interface(cfg, flask_webapp):
                       rest_entry('/login', rz_user.rest__login, {'methods': ['GET', 'POST']}),
                       rest_entry('/logout', rz_user.rest__logout, {'methods': ['GET', 'POST']}),
                       rest_entry('/match/node-set', rz_api.match_node_set_by_attr_filter_map),
+                      rest_entry('/pw-reset', rz_user.rest__pw_reset, {'methods': ['GET', 'POST']}),
                       rest_entry('/signup', rz_user.rest__user_signup, {'methods': ['GET', 'POST']}),
 
                       # server administration: access restricted to localhost
diff --git a/src/server/rz_user.py b/src/server/rz_user.py
index 6c649273..3808dbc9 100644
--- a/src/server/rz_user.py
+++ b/src/server/rz_user.py
@@ -166,6 +166,129 @@ def rest__logout():
     log.debug('logout: success: user: %s' % (u))
     return redirect(url_for('login'))
 
+def rest__pw_reset():
+
+    def get_or_init_pw_rst_req_map():
+        """
+        lazy pw reset request map getter. We map requests twice:
+           - once by email, to throttle reset requests per account
+           - second by security token, to allow lookup by supplied token on POST
+        """
+        if not hasattr(current_app, 'pw_rst_req_map'):
+            setattr(current_app, 'pw_rst_req_map', {})
+        return current_app.pw_rst_req_map
+
+    def sanitize_input(req):
+        """
+        here we expect a map of input-element id's to input-element values
+        """
+        req_json = request.get_json()
+        email_address = req_json.get('email_address')  # None when collecting the new password
+        new_user_pw = req_json.get('new_user_password')  # None when submitting initial reset request
+        pw_rst_tok = req_json.get('pw_rst_tok')  # None unless accepting new pw
+
+        if None != email_address:
+            regex__email_address = r'[^@]+@[^@]+\.[^@]+'
+            if None == re.match(regex__email_address, email_address):
+                raise Exception('malformed signup request: regex match failure: regex: %s, input: %s' % (regex__email_address, email_address))
+
+        if None != pw_rst_tok:
+            tmp_tok = generate_security_token()
+            if len(tmp_tok) != len(pw_rst_tok):
+                raise Exception('malformed signup request: malformed security token: %s' % (pw_rst_tok))
+
+        return {'email_address': email_address,
+                'new_user_pw': new_user_pw,
+                'pw_rst_tok': pw_rst_tok }
+
+    html_ok__submitted = '<p>Your request has been received.<br>Please check your email to reset your password.</p>'
+    html_ok__pw_updated = '<p>Your password has been successfully updated.<br>Please head over to the <a href="/login">login page</a> to access your account.'
+    html_ok__already_pending = '<p>Your request has already been submitted.<br>please check your email to proceed.</p>'
+    html_err__tech_difficulty = '<p>We are experiencing technical difficulty processing your request,<br>please try again later.</p>'
+
+    pw_rst_req_map = get_or_init_pw_rst_req_map()
+    filter_expired__pw_rst_requests(pw_rst_req_map)  # first do some housekeeping
+
+    if request.method == 'GET':
+
+        pw_rst_tok = request.args.get('pw_rst_tok')
+        if None == pw_rst_tok:  # request submission
+            return render_template('pw_reset.html', pw_rst_step='step_0__reset_request_submission')
+
+        else:  # token passed, perform request validation
+            pw_rst_req = pw_rst_req_map.get(pw_rst_tok)
+
+            if None == pw_rst_req:
+                # request expired & already removed OR bad token
+                log.warning('pw reset: request not found or bad token: remote-address: %s' % (request.remote_addr))
+                return render_template('pw_reset.html', pw_rst_step='general_error')
+
+            if pw_rst_req.has_expired():  # check again whether request has expired
+                log.warning('pw reset: attempt to activate expired reset request: email: %s' % (pw_rst_req.email_address))
+                return render_template('pw_reset.html', pw_rst_step='general_error')
+
+            return render_template('pw_reset.html', pw_rst_step='step_1__collect_new_password')
+
+    if request.method == 'POST':
+
+        req_data = sanitize_input(request)
+        user_db = current_app.user_db
+
+        pw_rst_tok = req_data.get('pw_rst_tok')
+        new_user_pw = req_data.get('new_user_pw')
+        email_address = req_data.get('email_address')
+
+        # handle according to passed req arguments
+        if pw_rst_tok and new_user_pw and None == email_address:  # validate token & collect new pw
+
+            uid = None
+
+            pw_rst_req = pw_rst_req_map.get(pw_rst_tok)
+            if None == pw_rst_req:
+                # request expired & already removed OR bad token
+                log.warning('pw reset: request not found or bad token: remote-address: %s' % (request.remote_addr))
+                return make_response__json__html(status=500, html_str=html_err__tech_difficulty)
+
+            # perform pw update
+            uid, u_account = user_db.lookup_user__by_email_address(pw_rst_req.u_account.email_address)
+            user_db.update_user_password(uid, new_user_pw)
+            del pw_rst_req_map[pw_rst_tok]  # rm request mapping: sec token
+            del pw_rst_req_map[u_account.email_address]  # rm request mapping: email address
+
+            log.info('pw reset: pw reset complete: u_account: %s' % (u_account))
+            return make_response__json__html(html_str=html_ok__pw_updated)
+
+        elif email_address and None == pw_rst_tok and None == new_user_pw:  # request submission
+
+            u_account = None
+
+            try:
+                uid, u_account = user_db.lookup_user__by_email_address(email_address)
+            except Exception as _:
+                log.exception('pw reset request for non-existing account: email_address: %s' % (email_address))
+                return make_response__json__html(status=500, html_str=html_err__tech_difficulty)
+
+            if None != pw_rst_req_map.get(email_address):  # probe for pending requests
+                return make_response__json__html(html_str=html_ok__already_pending)
+
+            pw_rst_tok = generate_security_token()
+            pw_rst_req = User_Pw_Reset_Request(u_account, pw_rst_tok)
+
+            try:
+                pw_reset_link = send_user_pw_reset__email(u_account, pw_rst_tok)
+                pw_rst_req.submission_date = datetime.now()  # mark submission date
+                pw_rst_req_map[pw_rst_tok] = pw_rst_req
+                pw_rst_req_map[email_address] = pw_rst_req
+
+                log.info('pw reset: req received, reset link sent via email: link: %s' % (pw_reset_link))
+                return make_response__json__html(html_str=html_ok__submitted)
+
+            except Exception as _:
+                return make_response__json__html(status=500, html_str=html_err__tech_difficulty)
+
+        else:  # weird state: missing / unnecessary post fields
+            return make_response__json__html(status=500, html_str=html_err__tech_difficulty)
+
 def rest__user_signup():
     """
     REST API endpoint: user sign up
@@ -323,3 +446,33 @@ def send_user_activation_link__email(us_req):
                        subject="Rhizi sign up request",
                        body=msg_body)
     return activation_link
+
+def send_user_pw_reset__email(u_account, pw_reset_token):
+    """
+    Send user pw reset email
+    
+    @return: pw reset link
+    @raise exception: on send error
+    """
+
+    # FIXME: use HTTPS
+    pw_reset_link = 'http://%s/pw-reset?pw_rst_tok=%s' % (current_app.rz_config.SERVER_NAME,
+                                                          pw_reset_token)
+
+    msg_body = ['Hello %s %s,' % (u_account.first_name,
+                                  u_account.last_name),
+                '',
+                'A password reset request has been received for this email address.',
+                'Please follow the link below to reset the password for your account:',
+                '',
+                pw_reset_link,
+                '',
+                'Happy knowledge editing!',
+                'The Rhizi team.'
+                ]
+    msg_body = '\n'.join(msg_body)
+
+    send_email_message(recipients=[u_account.email_address],
+                       subject="Rhizi sign up request",
+                       body=msg_body)
+    return pw_reset_link