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EWF/library/server/wsf/router/policy/wsf_method_helper.e

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note
description: "[
Policy-driven helpers to implement a method.
]"
date: "$Date$"
revision: "$Revision$"
deferred class WSF_METHOD_HELPER
inherit
HTTP_STATUS_CODE_MESSAGES
SHARED_HTML_ENCODER
export {NONE} all end
feature -- Access
resource_exists: BOOLEAN
-- Does the requested resource (request URI) exist?
feature -- Setting
set_resource_exists
-- Set `resource_exists' to `True'.
do
resource_exists := True
ensure
set: resource_exists
end
feature -- Basic operations
execute_new_resource (req: WSF_REQUEST; res: WSF_RESPONSE; a_handler: WSF_SKELETON_HANDLER)
-- Write response to non-existing resource requested by `req.' into `res'.
-- Policy routines are available in `a_handler'.
-- Upto four execution variables may be set on `req':
-- "NEGOTIATED_MEDIA_TYPE"
-- "NEGOTIATED_LANGUAGE"
-- "NEGOTIATED_CHARSET"
-- "NEGOTIATED_ENCODING"
-- An HTTP_HEADER is also available as the execution variable "NEGOTIATED_HTTP_HEADER".
-- It includes the Vary header (if any)
require
req_attached: req /= Void
res_attached: res /= Void
a_handler_attached: a_handler /= Void
local
l_locs: LIST [URI]
do
if a_handler.resource_previously_existed (req) then
if a_handler.resource_moved_permanently (req) then
l_locs := a_handler.previous_location (req)
handle_redirection_error (req, res, l_locs, {HTTP_STATUS_CODE}.moved_permanently)
elseif a_handler.resource_moved_temporarily (req) then
l_locs := a_handler.previous_location (req)
handle_redirection_error (req, res, l_locs, {HTTP_STATUS_CODE}.found)
else
check attached {HTTP_HEADER} req.execution_variable (a_handler.Negotiated_http_header_execution_variable) as h then
-- postcondition header_attached of `handle_content_negotiation'
h.put_content_type_text_plain
h.put_current_date
h.put_content_length (0)
res.set_status_code ({HTTP_STATUS_CODE}.gone)
res.put_header_lines (h)
end
end
else
check attached {HTTP_HEADER} req.execution_variable (a_handler.Negotiated_http_header_execution_variable) as h then
-- postcondition header_attached of `handle_content_negotiation'
h.put_content_type_text_plain
h.put_current_date
h.put_content_length (0)
res.set_status_code ({HTTP_STATUS_CODE}.not_found)
res.put_header_lines (h)
end
end
end
execute_existing_resource (req: WSF_REQUEST; res: WSF_RESPONSE; a_handler: WSF_SKELETON_HANDLER)
-- Write response to existing resource requested by `req' into `res'.
-- Policy routines are available in `a_handler'.
-- Upto four execution variables may be set on `req':
-- "NEGOTIATED_MEDIA_TYPE"
-- "NEGOTIATED_LANGUAGE"
-- "NEGOTIATED_CHARSET"
-- "NEGOTIATED_ENCODING"
require
req_attached: req /= Void
res_attached: res /= Void
a_handler_attached: a_handler /= Void
not_if_match_star: attached req.http_if_match as l_if_match implies not l_if_match.same_string ("*")
local
l_etags: LIST [READABLE_STRING_8]
l_failed: BOOLEAN
l_date: HTTP_DATE
do
if attached req.http_if_match as l_if_match then
-- also if-range when we add support for range requests
if not l_if_match.same_string ("*") then
l_etags := l_if_match.split (',')
l_failed := not across l_etags as i_etags some a_handler.matching_etag (req, i_etags.item, True) end
end
end
if l_failed then
handle_precondition_failed (req, res)
else
if attached req.http_if_unmodified_since as l_if_unmodified_since then
if l_if_unmodified_since.is_string_8 then
create l_date.make_from_string (l_if_unmodified_since.as_string_8)
if not l_date.has_error then
if a_handler.modified_since (req, l_date.date_time) then
handle_precondition_failed (req, res)
l_failed := True
end
end
end
end
if not l_failed then
if attached req.http_if_none_match as l_if_none_match then
l_etags := l_if_none_match.split (',')
l_failed := l_if_none_match.same_string ("*") or
across l_etags as i_etags some a_handler.matching_etag (req, i_etags.item, False) end
end
if l_failed then
handle_if_none_match_failed (req, res, a_handler)
else
if attached req.http_if_modified_since as l_if_modified_since then
if l_if_modified_since.is_string_8 then
create l_date.make_from_string (l_if_modified_since.as_string_8)
if not l_date.has_error then
if not a_handler.modified_since (req, l_date.date_time) then
handle_not_modified (req, res, a_handler)
l_failed := True
end
end
end
end
end
if not l_failed then
check attached {HTTP_HEADER} req.execution_variable (a_handler.Negotiated_http_header_execution_variable) as h then
-- postcondition header_attached of `handle_content_negotiation'
send_response (req, res, a_handler, h, False)
end
end
end
end
end
feature -- Content negotiation
handle_content_negotiation (req: WSF_REQUEST; res: WSF_RESPONSE; a_handler: WSF_SKELETON_HANDLER)
-- Negotiate acceptable content for, then write, response requested by `req' into `res'.
-- Policy routines are available in `a_handler'.
--
-- Either a 406 Not Acceptable error is sent, or upto four execution variables may be set on `req':
-- "NEGOTIATED_MEDIA_TYPE"
-- "NEGOTIATED_LANGUAGE"
-- "NEGOTIATED_CHARSET"
-- "NEGOTIATED_ENCODING"
-- An HTTP_HEADER is also saved as the execution variable "NEGOTIATED_HTTP_HEADER".
-- It includes the Vary header (if any)
require
req_attached: req /= Void
res_attached: res /= Void
a_handler_attached: a_handler /= Void
local
l_conneg: CONNEG_SERVER_SIDE
h: HTTP_HEADER
l_media: MEDIA_TYPE_VARIANT_RESULTS
l_lang: LANGUAGE_VARIANT_RESULTS
l_charset: CHARACTER_ENCODING_VARIANT_RESULTS
l_encoding: COMPRESSION_VARIANT_RESULTS
l_mime_types, l_langs, l_charsets, l_encodings: LIST [STRING]
l_vary_star: BOOLEAN
do
create h.make
l_vary_star := not a_handler.predictable_response (req)
if l_vary_star then
h.add_header_key_value ({HTTP_HEADER_NAMES}.header_vary, "*")
elseif attached a_handler.additional_variant_headers (req) as l_additional then
across l_additional as i_additional loop
h.add_header_key_value ({HTTP_HEADER_NAMES}.header_vary, i_additional.item)
end
end
l_conneg := a_handler.conneg (req)
l_mime_types := a_handler.mime_types_supported (req)
l_media := l_conneg.media_type_preference (l_mime_types, req.http_accept)
if not l_vary_star and l_mime_types.count > 1 and attached l_media.variant_header as l_media_variant then
h.add_header_key_value ({HTTP_HEADER_NAMES}.header_vary, l_media_variant)
end
if not l_media.is_acceptable then
handle_not_acceptable ("None of the requested ContentTypes were acceptable", l_mime_types, req, res)
else
l_langs := a_handler.languages_supported (req)
l_lang := l_conneg.language_preference (l_langs, req.http_accept_language)
if not l_vary_star and l_langs.count > 1 and attached l_lang.variant_header as l_lang_variant then
h.add_header_key_value ({HTTP_HEADER_NAMES}.header_vary, l_lang_variant)
end
if not l_lang.is_acceptable then
handle_not_acceptable ("None of the requested languages were acceptable", l_langs, req, res)
else
if attached l_lang.language_type as l_language_type then
h.put_content_language (l_language_type)
req.set_execution_variable (a_handler.Negotiated_language_execution_variable, l_language_type)
end
l_charsets := a_handler.charsets_supported (req)
l_charset := l_conneg.charset_preference (l_charsets, req.http_accept_charset)
if not l_vary_star and l_charsets.count > 1 and attached l_charset.variant_header as l_charset_variant then
h.add_header_key_value ({HTTP_HEADER_NAMES}.header_vary, l_charset_variant)
end
if not l_charset.is_acceptable then
handle_not_acceptable ("None of the requested character encodings were acceptable", l_charsets, req, res)
else
if attached l_media.media_type as l_media_type then
if attached l_charset.character_type as l_character_type then
h.put_content_type (l_media_type + "; charset=" + l_character_type)
req.set_execution_variable (a_handler.Negotiated_charset_execution_variable, l_charset)
else
h.put_content_type (l_media_type)
end
req.set_execution_variable (a_handler.Negotiated_media_type_execution_variable, l_media_type)
end
l_encodings := a_handler.encodings_supported (req)
l_encoding := l_conneg.encoding_preference (l_encodings, req.http_accept_encoding)
if not l_vary_star and l_encodings.count > 1 and attached l_encoding.variant_header as l_encoding_variant then
h.add_header_key_value ({HTTP_HEADER_NAMES}.header_vary, l_encoding_variant)
end
if not l_encoding.is_acceptable then
handle_not_acceptable ("None of the requested transfer encodings were acceptable", l_encodings, req, res)
else
if attached l_encoding.compression_type as l_compression_type then
h.put_content_encoding (l_compression_type)
req.set_execution_variable (a_handler.Negotiated_encoding_execution_variable, l_compression_type)
end
end
end
end
end
req.set_execution_variable (a_handler.Negotiated_http_header_execution_variable, h)
ensure
header_attached: attached {HTTP_HEADER} req.execution_variable (a_handler.Negotiated_http_header_execution_variable)
end
feature {NONE} -- Implementation
send_response (req: WSF_REQUEST; res: WSF_RESPONSE; a_handler: WSF_SKELETON_HANDLER; a_header: HTTP_HEADER; a_new_resource: BOOLEAN)
-- Write response to `req' into `res'.
-- Upto four execution variables may be set on `req':
-- "NEGOTIATED_MEDIA_TYPE"
-- "NEGOTIATED_LANGUAGE"
-- "NEGOTIATED_CHARSET"
-- "NEGOTIATED_ENCODING"
require
req_attached: req /= Void
res_attached: res /= Void
a_handler_attached: a_handler /= Void
a_header_attached: a_header /= Void
deferred
end
send_chunked_response (req: WSF_REQUEST; res: WSF_RESPONSE; a_handler: WSF_SKELETON_HANDLER; a_header: HTTP_HEADER)
-- Write response in chunks to `req'.
-- Upto four execution variables may be set on `req':
-- "NEGOTIATED_MEDIA_TYPE"
-- "NEGOTIATED_LANGUAGE"
-- "NEGOTIATED_CHARSET"
-- "NEGOTIATED_ENCODING"
require
req_attached: req /= Void
res_attached: res /= Void
a_handler_attached: a_handler /= Void
local
l_chunk: TUPLE [a_chunk: READABLE_STRING_8; a_extension: detachable READABLE_STRING_8]
do
from
if a_handler.response_ok (req) then
l_chunk := a_handler.next_chunk (req)
res.put_chunk (l_chunk.a_chunk, l_chunk.a_extension)
else
write_error_response (req, res)
end
until
a_handler.finished (req) or not a_handler.response_ok (req)
loop
a_handler.generate_next_chunk (req)
if a_handler.response_ok (req) then
l_chunk := a_handler.next_chunk (req)
res.put_chunk (l_chunk.a_chunk, l_chunk.a_extension)
else
write_error_response (req, res)
end
end
if a_handler.finished (req) then
-- In future, add support for trailers
res.put_chunk_end
end
end
generate_cache_headers (req: WSF_REQUEST; a_handler: WSF_SKELETON_HANDLER; a_header: HTTP_HEADER; a_request_time: DATE_TIME)
-- Write headers affecting caching for `req' into `a_header'.
require
req_attached: req /= Void
a_handler_attached: a_handler /= Void
a_header_attached: a_header /= Void
a_request_time_attached: a_request_time /= Void
local
l_age, l_age_1, l_age_2: NATURAL
l_dur: DATE_TIME_DURATION
l_dt, l_field_names: STRING
do
l_age := a_handler.http_1_0_age (req)
create l_dur.make (0, 0, 0, 0, 0, l_age.as_integer_32)
l_dt := (create {HTTP_DATE}.make_from_date_time (a_request_time + l_dur)).rfc1123_string
a_header.put_header_key_value ({HTTP_HEADER_NAMES}.header_expires, l_dt)
l_age_1 := a_handler.max_age (req)
if l_age_1 /= l_age then
a_header.add_header_key_value ({HTTP_HEADER_NAMES}.header_cache_control, "max-age=" + l_age_1.out)
end
l_age_2 := a_handler.shared_age (req)
if l_age_2 /= l_age_1 then
a_header.add_header_key_value ({HTTP_HEADER_NAMES}.header_cache_control, "s-maxage=" + l_age_2.out)
end
if a_handler.is_freely_cacheable (req) then
a_header.add_header_key_value ({HTTP_HEADER_NAMES}.header_cache_control, "public")
elseif attached a_handler.private_headers (req) as l_fields then
l_field_names := "="
if not l_fields.is_empty then
append_field_name (l_field_names, l_fields)
end
a_header.add_header_key_value ({HTTP_HEADER_NAMES}.header_cache_control, "private" + l_field_names)
end
if attached a_handler.non_cacheable_headers (req) as l_fields then
l_field_names := "="
if not l_fields.is_empty then
append_field_name (l_field_names, l_fields)
end
a_header.add_header_key_value ({HTTP_HEADER_NAMES}.header_cache_control, "no-cache" + l_field_names)
end
if not a_handler.is_transformable (req) then
a_header.add_header_key_value ({HTTP_HEADER_NAMES}.header_cache_control, "no-transform")
end
if a_handler.must_revalidate (req) then
a_header.add_header_key_value ({HTTP_HEADER_NAMES}.header_cache_control, "must-revalidate")
end
if a_handler.must_proxy_revalidate (req) then
a_header.add_header_key_value ({HTTP_HEADER_NAMES}.header_cache_control, "proxy-revalidate")
end
end
append_field_name (a_field_names: STRING; a_fields: LIST [READABLE_STRING_8])
-- Append all of `a_fields' as a comma-separated list to `a_field_names'.
require
a_field_names_attached: a_field_names /= Void
a_fields_attached: a_fields /= Void
do
across a_fields as i_fields loop
a_field_names.append_string (i_fields.item)
if not i_fields.is_last then
a_field_names.append_character (',')
end
end
end
feature -- Error reporting
write_error_response (req: WSF_REQUEST; res: WSF_RESPONSE)
-- Write an error response to `res' using `req.error_handler'.
require
req_attached: req /= Void
res_attached: res /= Void
req_has_error: req.has_error
local
h: HTTP_HEADER
m: READABLE_STRING_8
do
m := req.error_handler.as_string_representation
create h.make
h.put_content_type_text_plain
h.put_content_length (m.count)
res.set_status_code (req.error_handler.primary_error_code)
res.put_header_lines (h)
res.put_string (m)
end
handle_redirection_error (req: WSF_REQUEST; res: WSF_RESPONSE; a_locations: LIST [URI]; a_status_code: INTEGER)
-- Write `a_status_code' error to `res'.
-- Include all of `a_locations' in the headers, and hyperlink to the first one in the body.
require
res_attached: res /= Void
req_attached: req /= Void
a_locations_attached: a_locations /= Void
a_location_not_empty: not a_locations.is_empty
a_status_code_code: is_valid_http_status_code (a_status_code)
local
h: HTTP_HEADER
s: STRING
do
if attached http_status_code_message (a_status_code) as l_msg then
create h.make
across a_locations as i_location loop
h.add_header_key_value ({HTTP_HEADER_NAMES}.header_location, i_location.item.string)
end
if req.is_content_type_accepted ({HTTP_MIME_TYPES}.text_html) then
s := "<html lang=%"en%"><head>"
s.append ("<title>")
s.append (html_encoder.encoded_string (req.request_uri))
s.append ("Error " + a_status_code.out + " (" + l_msg + ")")
s.append ("</title>%N")
s.append ("[
<style type="text/css">
div#header {color: #fff; background-color: #000; padding: 20px; text-align: center; font-size: 2em; font-weight: bold;}
div#message { margin: 40px; text-align: center; font-size: 1.5em; }
div#suggestions { margin: auto; width: 60%;}
div#suggestions ul { }
div#footer {color: #999; background-color: #eee; padding: 10px; text-align: center; }
div#logo { float: right; margin: 20px; width: 60px height: auto; font-size: 0.8em; text-align: center; }
div#logo div.outer { padding: 6px; width: 60px; border: solid 3px #500; background-color: #b00;}
div#logo div.outer div.inner1 { display: block; margin: 10px 15px; width: 30px; height: 50px; color: #fff; background-color: #fff; border: solid 2px #900; }
div#logo div.outer div.inner2 { margin: 10px 15px; width: 30px; height: 15px; color: #fff; background-color: #fff; border: solid 2px #900; }
</style>
</head>
<body>
]")
s.append ("<div id=%"header%">Error " + a_status_code.out + " (" + l_msg + ")</div>")
s.append ("<div id=%"logo%">")
s.append ("<div class=%"outer%"> ")
s.append ("<div class=%"inner1%"></div>")
s.append ("<div class=%"inner2%"></div>")
s.append ("</div>")
s.append ("The current location for this resource is <a href=%"" + a_locations.first.string + "%">here</a>")
s.append ("Error " + a_status_code.out + " (" + l_msg + ")</div>")
s.append ("<div id=%"message%">Error " + a_status_code.out + " (" + l_msg + "): <code>" + html_encoder.encoded_string (req.request_uri) + "</code></div>")
s.append ("<div id=%"footer%"></div>")
s.append ("</body>%N")
s.append ("</html>%N")
h.put_content_type_text_html
else
s := "Error " + a_status_code.out + " (" + l_msg + "): "
s.append (req.request_uri)
s.append_character ('%N')
s.append ("The current location for this resource is " + a_locations.first.string)
h.put_content_type_text_plain
end
h.put_content_length (s.count)
res.put_header_lines (h)
res.put_string (s)
res.flush
end
end
handle_not_acceptable (a_message: READABLE_STRING_8; a_supported: LIST [STRING]; req: WSF_REQUEST; res: WSF_RESPONSE)
-- Write a Not Acceptable response to `res'.
require
req_attached: req /= Void
res_attached: res /= Void
a_message_attached: a_message /= Void
a_supported_attached: a_supported /= Void
local
h: HTTP_HEADER
s: STRING
do
create h.make
h.put_content_type_text_plain
h.put_current_date
s := a_message
s.append_character ('%N')
s.append_character ('%N')
s.append_string ("We accept the following:%N%N")
across a_supported as i_supported loop
s.append_string (i_supported.item)
s.append_character ('%N')
end
h.put_content_length (s.count)
res.set_status_code ({HTTP_STATUS_CODE}.not_acceptable)
res.put_header_lines (h)
res.put_string (s)
res.flush
end
handle_if_none_match_failed (req: WSF_REQUEST; res: WSF_RESPONSE; a_handler: WSF_SKELETON_HANDLER)
-- Write a Not Modified response to `res'.
require
req_attached: req /= Void
res_attached: res /= Void
a_handler_attached: a_handler /= Void
do
handle_not_modified (req, res, a_handler)
end
handle_not_modified (req: WSF_REQUEST; res: WSF_RESPONSE; a_handler: WSF_SKELETON_HANDLER)
-- Write a Not Modified response to `res'.
-- Upto four execution variables may be set on `req':
-- "NEGOTIATED_MEDIA_TYPE"
-- "NEGOTIATED_LANGUAGE"
-- "NEGOTIATED_CHARSET"
-- "NEGOTIATED_ENCODING"
require
req_attached: req /= Void
res_attached: res /= Void
a_handler_attached: a_handler /= Void
local
h: HTTP_HEADER
do
create h.make
h.put_content_type_text_plain
h.put_content_length (0)
if attached a_handler.etag (req) as l_etag then
h.put_header_key_value ({HTTP_HEADER_NAMES}.header_etag, l_etag)
end
generate_cache_headers (req, a_handler, h, create {DATE_TIME}.make_now_utc)
res.set_status_code ({HTTP_STATUS_CODE}.not_modified)
res.put_header_lines (h)
end
handle_precondition_failed (req: WSF_REQUEST; res: WSF_RESPONSE)
-- Write a Precondition Failed response for `req' to `res'.
require
req_attached: req /= Void
res_attached: res /= Void
local
h: HTTP_HEADER
do
create h.make
h.put_content_type_text_plain
h.put_current_date
h.put_content_length (0)
res.set_status_code ({HTTP_STATUS_CODE}.precondition_failed)
res.put_header_lines (h)
end
handle_unsupported_media_type (req: WSF_REQUEST; res: WSF_RESPONSE)
-- Write a Unsupported Media Type response for `req' to `res'.
require
req_attached: req /= Void
res_attached: res /= Void
local
h: HTTP_HEADER
do
create h.make
h.put_content_type_text_plain
h.put_current_date
h.put_content_length (0)
res.set_status_code ({HTTP_STATUS_CODE}.unsupported_media_type)
res.put_header_lines (h)
end
handle_not_implemented (req: WSF_REQUEST; res: WSF_RESPONSE)
-- Write a Not Implemented response for `req' to `res'.
require
req_attached: req /= Void
res_attached: res /= Void
local
h: HTTP_HEADER
do
create h.make
h.put_content_type_text_plain
h.put_current_date
h.put_content_length (0)
res.set_status_code ({HTTP_STATUS_CODE}.not_implemented)
res.put_header_lines (h)
end
handle_request_entity_too_large (req: WSF_REQUEST; res: WSF_RESPONSE; a_handler: WSF_SKELETON_HANDLER)
-- Write a Request Entity Too Large response for `req' to `res'.
require
req_attached: req /= Void
res_attached: res /= Void
a_handler_attached: a_handler /= Void
local
h: HTTP_HEADER
do
create h.make
h.put_content_type_text_plain
h.put_current_date
h.put_content_length (0)
res.set_status_code ({HTTP_STATUS_CODE}.request_entity_too_large)
res.put_header_lines (h)
-- FIXME: Need to check if condition is temporary. This needs a new query
-- on the handler. For now we can claim compliance by saying the condition
-- is always permenent :-) - author's might not like this though.
end
note
copyright: "2011-2013, Jocelyn Fiat, Javier Velilla, Olivier Ligot, Eiffel Software and others"
license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
source: "[
Eiffel Software
5949 Hollister Ave., Goleta, CA 93117 USA
Telephone 805-685-1006, Fax 805-685-6869
Website http://www.eiffel.com
Customer support http://support.eiffel.com
]"
end