37 KiB
37 KiB
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Nav: Workbook :: Handling Requests: Header Fields :: Handling Cookies
EWF Generating Response
Table of Contents
- Format of the HTTP response
- How to set status code
- How to redirect to a particular location.
- HTTP Status codes
- Example Staus Codes
- Generic Search Engine
- Response Header Fields
Format of the HTTP response
As we saw in the previous documents, a request from a user-agent (browser or other client) consists of an HTTP command (usually GET or POST), zero or more request headers (one or more in HTTP 1.1, since Host is required), a blank line, and only in the case of POST/PUT requests, payload data. A typical request looks like the following.
GET /url[query_string] HTTP/1.1
Host: ...
Header2: ...
...
HeaderN:
(Blank Line)
When a Web server responds to a request, the response typically consists of a status line, some response headers, a blank line, and the document. A typical response looks like this:
HTTP/1.1 200 OK
Content-Type: text/html
Header2: ...
...
HeaderN: ...
(Blank Line)
<!DOCTYPE ...>
<HTML>
<HEAD>...</HEAD>
<BODY>
...
</BODY>
</HTML>
The status line consists of the HTTP version (HTTP/1.1 in the preceding example), a status code (an integer 200 in the example), and a very short message corresponding to the status code (OK in the example). In most cases, the headers are optional except for Content-Type, which specifies the MIME type of the document that follows. Although most responses contain a document, some don’t. For example, responses to HEAD requests should never include a document, and various status codes essentially indicate failure or redirection (and thus either don’t include a document or include only a short error-message document).
How to set the status code
If you need to set an arbitrary status code, you can use the WSF_RESPONSE.put_header feature or the WSF_RESPONSE.set_status_code feature. An status code of 200 is a default value. See below examples using the mentioned features.
Using the WSF_RESPONSE.put_header feature.
In this case you provide the status code with a collection of headers.
put_header (a_status_code: INTEGER_32; a_headers: detachable ARRAY [TUPLE [name: READABLE_STRING_8; value: READABLE_STRING_8]])
-- Put headers with status `a_status', and headers from `a_headers'
require
a_status_code_valid: a_status_code > 0
status_not_committed: not status_committed
header_not_committed: not header_committed
ensure
status_code_set: status_code = a_status_code
status_set: status_is_set
message_writable: message_writable
Example
res.put_header ({HTTP_STATUS_CODE}.ok, <<["Content-Type", "text/html"], ["Content-Length", output_size]>>)
res.put_string (web_page)
Using the WSF_RESPONSE.set_status code
custom_response (req: WSF_REQUEST; res: WSF_RESPONSE; output: STRING)
local
h: HTTP_HEADER
l_msg: STRING
do
create h.make
create l_msg.make_from_string (output)
h.put_content_type_text_html
h.put_content_length (l_msg.count)
h.put_current_date
res.set_status_code ({HTTP_STATUS_CODE}.ok)
res.put_header_text (h.string)
res.put_string (l_msg)
end
Both features takes an INTEGER (the status code) as an formal argument, you can use 200, 300, 500 etc directly, but instead of using explicit numbers, it's recommended to use the constants defined in the class HTTP_STATUS_CODE. The name of each constant is based from the standard HTTP 1.1.
How to redirect to a particular location.
To redirect the response to a new location, we need to send a 302 status code, to do that we use {HTTP_STATUS_CODE}.found
The 302 (Found) status code indicates that the target resource resides temporarily under a different URI. Since the redirection might be altered on occasion, the client ought to continue to use the effective request URI for future requests.
Another way to do redirection is with 303 status code
The 303 (See Other) status code indicates that the server is redirecting the user agent to a different resource, as indicated by a URI in the Location header field, which is intended to provide an indirect response to the original request.
The next code show a custom feature to write a redirection, you can use found or see_other based on your particular requirements.
send_redirect (req: WSF_REQUEST; res: WSF_RESPONSE; a_location: READABLE_STRING_32)
-- Redirect to `a_location'
local
h: HTTP_HEADER
do
create h.make
h.put_content_type_text_html
h.put_current_date
h.put_location (a_location)
res.set_status_code ({HTTP_STATUS_CODE}.found)
res.put_header_text (h.string)
end
The class WSF_RESPONSE provide features to work with redirection
redirect_now (a_url: READABLE_STRING_8)
-- Redirect to the given url `a_url'
require
header_not_committed: not header_committed
redirect_now_custom (a_url: READABLE_STRING_8; a_status_code: INTEGER_32; a_header: detachable HTTP_HEADER; a_content: detachable TUPLE [body: READABLE_STRING_8; type: READABLE_STRING_8])
-- Redirect to the given url `a_url' and precise custom `a_status_code', custom header and content
-- Please see http://www.faqs.org/rfcs/rfc2616 to use proper status code.
-- if `a_status_code' is 0, use the default {HTTP_STATUS_CODE}.temp_redirect
require
header_not_committed: not header_committed
redirect_now_with_content (a_url: READABLE_STRING_8; a_content: READABLE_STRING_8; a_content_type: READABLE_STRING_8)
-- Redirect to the given url `a_url'
The WSF_RESPONSE.redirect_now feature use the status code {HTTP_STATUS_CODE}.found,the other redirect features enable customize the status code and content based on your requirements.
Using a similar approach we can build features to answer a bad request (400), internal server error (500), etc. We will build a simple example showing the most common HTTP status codes.
HTTP 1.1 Status Codes
The status-code element is a three-digit integer code giving the result of the attempt to understand and satisfy the request. The first digit of the status-code defines the class of response.
General categories:
- 1xx Informational: The 1xx series of response codes are used only in negotiations with the HTTP server.
- 2xx Sucessful: The 2xx error codes indicate that an operation was successful.
- 3xx Redirection: The 3xx status codes indicate that the client needs to do some extra work to get what it wants.
- 4xx Client Error: These status codes indicate that something is wrong on the client side.
- 5xx Server Error: These status codes indicate that something is wrong on the server side.
Note: use res.set_status_code({HTTP_STATUS_CODE}.bad_request) rather than res.set_status_code(400).
Example Staus Codes
Basic Service that builds a simple web page to show the most common status codes
class
APPLICATION_EXECUTION
inherit
WSF_EXECUTION
create
make
feature -- Basic operations
execute (req: WSF_REQUEST; res: WSF_RESPONSE)
-- Execute the incomming request
local
l_message: STRING
do
-- To send a response we need to setup, the status code and
-- the response headers.
if req.is_get_request_method then
if req.path_info.same_string ("/") then
res.put_header ({HTTP_STATUS_CODE}.ok, <<["Content-Type", "text/html"], ["Content-Length", web_page.count.out]>>)
res.put_string (web_page)
elseif req.path_info.same_string ("/redirect") then
send_redirect (req, res, "https://httpwg.github.io/")
-- res.redirect_now (l_engine_url)
elseif req.path_info.same_string ("/bad_request") then
-- Here you can do some logic for example log, send emails to register the error, before to send the response.
create l_message.make_from_string (message_template)
l_message.replace_substring_all ("$title", "Bad Request")
l_message.replace_substring_all ("$status", "Bad Request 400")
res.put_header ({HTTP_STATUS_CODE}.bad_request, <<["Content-Type", "text/html"], ["Content-Length", l_message.count.out]>>)
res.put_string (l_message)
elseif req.path_info.same_string ("/internal_error") then
-- Here you can do some logic for example log, send emails to register the error, before to send the response.
create l_message.make_from_string (message_template)
l_message.replace_substring_all ("$title", "Internal Server Error")
l_message.replace_substring_all ("$status", "Internal Server Error 500")
res.put_header ({HTTP_STATUS_CODE}.internal_server_error, <<["Content-Type", "text/html"], ["Content-Length", l_message.count.out]>>)
res.put_string (l_message)
else
create l_message.make_from_string (message_template)
l_message.replace_substring_all ("$title", "Resource not found")
l_message.replace_substring_all ("$status", "Resource not found 400")
res.put_header ({HTTP_STATUS_CODE}.not_found, <<["Content-Type", "text/html"], ["Content-Length", l_message.count.out]>>)
res.put_string (l_message)
end
else
create l_message.make_from_string (message_template)
l_message.replace_substring_all ("$title", "Method Not Allowed")
l_message.replace_substring_all ("$status", "Method Not Allowed 405")
-- Method not allowed
res.put_header ({HTTP_STATUS_CODE}.method_not_allowed, <<["Content-Type", "text/html"], ["Content-Length", l_message.count.out]>>)
res.put_string (l_message)
end
end
feature -- Home Page
send_redirect (req: WSF_REQUEST; res: WSF_RESPONSE; a_location: READABLE_STRING_32)
-- Redirect to `a_location'
local
h: HTTP_HEADER
do
create h.make
h.put_content_type_text_html
h.put_current_date
h.put_location (a_location)
res.set_status_code ({HTTP_STATUS_CODE}.see_other)
res.put_header_text (h.string)
end
web_page: STRING = "[
<!DOCTYPE html>
<html>
<head>
<title>Example showing common status codes</title>
</head>
<body>
<div id="header">
<p id="name">Use a tool to see the request and header details, for example (Developers tools in Chrome or Firebugs in Firefox)</p>
</div>
<div class="left"></div>
<div class="right">
<h4>This page is an example of Status Code 200</h4>
<h4> Redirect Example </h4>
<p> Click on the following link will redirect you to the HTTP Specifcation, we can do the redirect from the HTML directly but
here we want to show you an exmaple, where you can do something before to send a redirect <a href="/redirect">Redirect</a></p>
<h4> Bad Request </h4>
<p> Click on the following link, the server will answer with a 400 error, check the status code <a href="/bad_request">Bad Request</a></p>
<h4> Internal Server Error </h4>
<p> Click on the following link, the server will answer with a 500 error, check the status code <a href="/internal_error">Internal Error</a></p>
<h4> Resource not found </h4>
<p> Click on the following link or add to the end of the url something like /1030303 the server will answer with a 404 error, check the status code <a href="/not_foundd">Not found</a></p>
</div>
<div id="footer">
<p>Useful links for status codes <a href="httpstat.us">httpstat.us</a> and <a href="httpbing.org">httpbin.org</a></p>
</div>
</body>
</html>
]"
feature -- Generic Message
message_template: STRING="[
<!DOCTYPE html>
<html>
<head>
<title>$title</title>
</head>
<body>
<div id="header">
<p id="name">Use a tool to see the request and header details, for example (Developers tools in Chrome or Firebugs in Firefox)</p>
</div>
<div class="left"></div>
<div class="right">
<h4>This page is an example of $status</h4>
<div id="footer">
<p><a href="/">Back Home</a></p>
</div>
</body>
</html>
]"
end
Example Generic Search Engine
The following example shows a basic EWF service that builds a generic front end for the most used search engines. This example shows how redirection works, and we will use a tools to play with the API to show differents responses.
note
description : "Basic Service that build a generic front end for the most used search engines."
date : "$Date$"
revision : "$Revision$"
class
APPLICATION_EXECUTION
inherit
WSF_EXECUTION
create
make
feature -- Basic operations
execute (req: WSF_REQUEST; res: WSF_RESPONSE)
-- Execute the incomming request
local
l_message: STRING
do
-- To send a response we need to setup, the status code and
-- the response headers.
if req.is_get_request_method then
if req.path_info.same_string ("/") then
res.put_header ({HTTP_STATUS_CODE}.ok, <<["Content-Type", "text/html"], ["Content-Length", web_page.count.out]>>)
res.put_string (web_page)
else
send_resouce_not_found (req, res)
end
elseif req.is_post_request_method then
if req.path_info.same_string ("/search") then
if attached {WSF_STRING} req.form_parameter ("query") as l_query then
if attached {WSF_STRING} req.form_parameter ("engine") as l_engine then
if attached {STRING} map.at (l_engine.value) as l_engine_url then
l_engine_url.append (l_query.value)
send_redirect (req, res, l_engine_url)
else
send_bad_request (req, res, " <strong>search engine: " + l_engine.value + "</strong> not supported,<br> try with Google or Bing")
end
else
send_bad_request (req, res, " <strong>search engine</strong> not selected")
end
else
send_bad_request (req, res, " form_parameter <strong>query</strong> is not present")
end
else
send_resouce_not_found (req, res)
end
else
create l_message.make_from_string (message_template)
l_message.replace_substring_all ("$title", "Method Not Allowed")
l_message.replace_substring_all ("$status", "Method Not Allowed 405")
-- Method not allowed
res.put_header ({HTTP_STATUS_CODE}.method_not_allowed, <<["Content-Type", "text/html"], ["Content-Length", l_message.count.out]>>)
res.put_string (l_message)
end
end
feature -- Engine Map
map : STRING_TABLE[STRING]
do
create Result.make (2)
Result.put ("http://www.google.com/search?q=", "Google")
Result.put ("http://www.bing.com/search?q=", "Bing")
end
feature -- Redirect
send_redirect (req: WSF_REQUEST; res: WSF_RESPONSE; a_location: READABLE_STRING_32)
-- Redirect to `a_location'
local
h: HTTP_HEADER
do
create h.make
h.put_content_type_text_html
h.put_current_date
h.put_location (a_location)
res.set_status_code ({HTTP_STATUS_CODE}.see_other)
res.put_header_text (h.string)
end
feature -- Bad Request
send_bad_request (req: WSF_REQUEST; res: WSF_RESPONSE; description: STRING)
local
l_message: STRING
do
create l_message.make_from_string (message_template)
l_message.replace_substring_all ("$title", "Bad Request")
l_message.replace_substring_all ("$status", "Bad Request" + description)
res.put_header ({HTTP_STATUS_CODE}.bad_request, <<["Content-Type", "text/html"], ["Content-Length", l_message.count.out]>>)
res.put_string (l_message)
end
feature -- Resource not found
send_resouce_not_found (req: WSF_REQUEST; res: WSF_RESPONSE)
local
l_message: STRING
do
create l_message.make_from_string (message_template)
l_message.replace_substring_all ("$title", "Resource not found")
l_message.replace_substring_all ("$status", "Resource" + req.request_uri + "not found 404")
res.put_header ({HTTP_STATUS_CODE}.not_found, <<["Content-Type", "text/html"], ["Content-Length", l_message.count.out]>>)
res.put_string (l_message)
end
feature -- Home Page
web_page: STRING = "[
<!DOCTYPE html>
<html>
<head>
<title>Generic Search Engine</title>
</head>
<body>
<div class="right">
<h2>Generic Search Engine</h2>
<form method="POST" action="/search" target="_blank">
<fieldset>
Search: <input type="search" name="query" placeholder="EWF framework"><br>
<div>
<input type="radio" name="engine" value="Google" checked><img src="http://ebizmba.ebizmbainc.netdna-cdn.com/images/logos/google.gif" height="24" width="42">
</div>
<div>
<input type="radio" name="engine" value="Bing"><img src="http://ebizmba.ebizmbainc.netdna-cdn.com/images/logos/bing.gif" height="24" width="42">
</div><br>
</fieldset>
<input type="submit">
</form>
</div>
<div id="footer">
<p><a href="http://www.ebizmba.com/articles/search-engines">Top 15 Most Popular Search Engines | March 2015</a></p>
</div>
</body>
</html>
]"
feature -- Generic Message
message_template: STRING="[
<!DOCTYPE html>
<html>
<head>
<title>$title</title>
</head>
<body>
<div id="header">
<p id="name">Use a tool to see the request and header details, for example (Developers tools in Chrome or Firebugs in Firefox)</p>
</div>
<div class="left"></div>
<div class="right">
<h4>This page is an example of $status</h4>
<div id="footer">
<p><a href="/">Back Home</a></p>
</div>
</body>
</html>
]"
end
Using cURL to test the application
In the first call we use the res.redirect_now (l_engine_url) feature
#>curl -i -H -v -X POST -d "query=Eiffel&engine=Google" http://localhost:9090/search
HTTP/1.1 302 Found
Location: http://www.google.com/search?q=Eiffel
Content-Length: 0
Connection: close
Here we use our custom send_redirect feature call.
#>curl -i -H -v -X POST -d "query=Eiffel&engine=Google" http://localhost:9090/search
HTTP/1.1 303 See Other
Content-Type: text/html
Date: Fri, 06 Mar 2015 14:37:33 GMT
Location: http://www.google.com/search?q=Eiffel
Connection: close
Engine Ask Not supported
#>curl -i -H -v -X POST -d "query=Eiffel&engine=Ask" http://localhost:9090/search
HTTP/1.1 400 Bad Request
Content-Type: text/html
Content-Length: 503
Connection: close
<!DOCTYPE html>
<html>
<head>
<title>Bad Request</title>
</head>
<body>
<div id="header">
<p id="name">Use a tool to see the request and header details, for example (Developers tools in Chrome or Firebugs in Firefox)</p>
</div>
<div class="left"></div>
<div class="right">
<h4>This page is an example of Bad Request <strong>search engine: Ask</strong> not supported,<br> try with Google or Bing</h4>
<div id="footer">
<p><a href="/">Back Home</a></p>
</div>
</body>
</html>
Missing query form parameter
#>curl -i -H -v -X POST -d "engine=Google" http://localhost:9090/search
HTTP/1.1 400 Bad Request
Content-Type: text/html
Content-Length: 477
Connection: close
<!DOCTYPE html>
<html>
<head>
<title>Bad Request</title>
</head>
<body>
<div id="header">
<p id="name">Use a tool to see the request and header details, for example (Developers tools in Chrome or Firebugs in Firefox)</p>
</div>
<div class="left"></div>
<div class="right">
<h4>This page is an example of Bad Request form_parameter <strong>query</strong> is not present</h4>
<div id="footer">
<p><a href="/">Back Home</a></p>
</div>
</body>
</html>
Resource searchs not found
#>curl -i -H -v -X POST -d "query=Eiffel&engine=Google" http://localhost:9090/searchs
HTTP/1.1 404 Not Found
Content-Type: text/html
Content-Length: 449
Connection: close
<!DOCTYPE html>
<html>
<head>
<title>Resource not found</title>
</head>
<body>
<div id="header">
<p id="name">Use a tool to see the request and header details, for example (Developers tools in Chrome or Firebugs in Firefox)</p>
</div>
<div class="left"></div>
<div class="right">
<h4>This page is an example of Resource /searchs not found 404</h4>
<div id="footer">
<p><a href="/">Back Home</a></p>
</div>
</body>
</html>
Response Header Fields
The response header fields allow the server to pass additional information about the response beyond what is placed in the status-line. These header fields give information about the server, about further access to the target resource, or about related resources. We can specify cookies, page modification date (for caching), reload a page after a designated period of time, size of the document.
How to set response headers.
HTTP allows multiple occurrences of the same header name, the features put_XYZ replace existing headers with the same name and
features add_XYZ add headers that can lead to duplicated entries.
add_header_line (h: READABLE_STRING_8)
-- Add header `h'
-- This can lead to duplicated header entries
require
header_not_committed: not header_committed
add_header_text (a_text: READABLE_STRING_8)
-- Add the multiline header `a_text'
-- Does not replace existing header with same name
-- This could leads to multiple header with the same name
require
header_not_committed: not header_committed
a_text_ends_with_single_crlf: a_text.count > 2 implies not a_text.substring (a_text.count - 2, a_text.count).same_string ("%R%N")
a_text_does_not_end_with_double_crlf: a_text.count > 4 implies not a_text.substring (a_text.count - 4, a_text.count).same_string ("%R%N%R%N")
ensure
status_set: status_is_set
message_writable: message_writable
put_header_line (h: READABLE_STRING_8)
-- Put header `h'
-- Replace any existing value
require
header_not_committed: not header_committed
put_header_text (a_text: READABLE_STRING_8)
-- Put the multiline header `a_text'
-- Overwite potential existing header
require
header_not_committed: not header_committed
a_text_ends_with_single_crlf: a_text.count > 2 implies not a_text.substring (a_text.count - 2, a_text.count).same_string ("%R%N")
a_text_does_not_end_with_double_crlf: a_text.count > 4 implies not a_text.substring (a_text.count - 4, a_text.count).same_string ("%R%N%R%N")
ensure
message_writable: message_writable
helpers
add_header (a_status_code: INTEGER_32; a_headers: detachable ARRAY [TUPLE [name: READABLE_STRING_8; value: READABLE_STRING_8]])
-- Put headers with status `a_status', and headers from `a_headers'
require
a_status_code_valid: a_status_code > 0
status_not_committed: not status_committed
header_not_committed: not header_committed
ensure
status_code_set: status_code = a_status_code
status_set: status_is_set
message_writable: message_writable
add_header_lines (a_lines: ITERABLE [READABLE_STRING_8])
-- Add headers from `a_lines'
require
header_not_committed: not header_committed
put_header (a_status_code: INTEGER_32; a_headers: detachable ARRAY [TUPLE [name: READABLE_STRING_8; value: READABLE_STRING_8]])
-- Put headers with status `a_status', and headers from `a_headers'
require
a_status_code_valid: a_status_code > 0
status_not_committed: not status_committed
header_not_committed: not header_committed
ensure
status_code_set: status_code = a_status_code
status_set: status_is_set
message_writable: message_writable
put_header_lines (a_lines: ITERABLE [READABLE_STRING_8])
-- Put headers from `a_lines'
require
header_not_committed: not header_committed
The other way to build headers is using the class HTTP_HEADER, that provide routines to build a header. It's recomended to take a look at constants classes such as HTTP_MIME_TYPES,HTTP_HEADER_NAMES,HTTP_STATUS_CODE,HTTP_REQUEST_METHODS, or HTTP_CONSTANTS which groups them for convenience.
custom_answer (req: WSF_REQUEST; res: WSF_RESPONSE; output: STRING)
local
h: HTTP_HEADER
l_msg: STRING
do
create h.make
create l_msg.make_from_string (output)
h.put_content_type_text_html
h.put_content_length (l_msg.count)
h.put_current_date
res.set_status_code ({HTTP_STATUS_CODE}.bad_gateway)
res.put_header_text (h.string)
res.put_string (l_msg)
end
The class HTTP_HEADER also supplies a number of convenience routines for specifying common headers, in fact the features are inherited from the class [HTTP_HEADER_MODIFIER].
deferred class interface
HTTP_HEADER_MODIFIER
feature -- Access
date_to_rfc1123_http_date_format (dt: DATE_TIME): STRING_8
-- String representation of `dt' using the RFC 1123
item alias "[]" (a_header_name: READABLE_STRING_8): detachable READABLE_STRING_8 assign force
-- First header item found for `a_name' if any
feature -- Status report
has (a_name: READABLE_STRING_8): BOOLEAN
-- Has header item for `n'?
-- Was declared in HTTP_HEADER_MODIFIER as synonym of has_header_named.
has_content_length: BOOLEAN
-- Has header "Content-Length"
has_content_type: BOOLEAN
-- Has header "Content-Type"
has_header_named (a_name: READABLE_STRING_8): BOOLEAN
-- Has header item for `n'?
-- Was declared in HTTP_HEADER_MODIFIER as synonym of has.
has_transfer_encoding_chunked: BOOLEAN
-- Has "Transfer-Encoding: chunked" header
feature -- Access: deferred
new_cursor: INDEXABLE_ITERATION_CURSOR [READABLE_STRING_8]
-- Fresh cursor associated with current structure.
feature -- Authorization
put_authorization (a_authorization: READABLE_STRING_8)
-- Put `a_authorization' with "Authorization" header
-- The Authorization header is constructed as follows:
-- 1. Username and password are combined into a string "username:password".
-- 2. The resulting string literal is then encoded using Base64.
-- 3. The authorization method and a space, i.e. "Basic " is then put before the encoded string.
-- ex: Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==
feature -- Content related header
add_content_type (a_content_type: READABLE_STRING_8)
-- same as put_content_type, but allow multiple definition of "Content-Type"
add_content_type_with_charset (a_content_type: READABLE_STRING_8; a_charset: READABLE_STRING_8)
-- Same as put_content_type_with_charset, but allow multiple definition of "Content-Type".
add_content_type_with_name (a_content_type: READABLE_STRING_8; a_name: READABLE_STRING_8)
-- same as put_content_type_with_name, but allow multiple definition of "Content-Type"
add_content_type_with_parameters (a_content_type: READABLE_STRING_8; a_params: detachable ARRAY [TUPLE [name: READABLE_STRING_8; value: READABLE_STRING_8]])
-- Add header line "Content-Type:" + type `a_content_type' and extra paramaters `a_params'.
put_content_disposition (a_type: READABLE_STRING_8; a_params: detachable READABLE_STRING_8)
-- Put "Content-Disposition" header
put_content_encoding (a_encoding: READABLE_STRING_8)
-- Put "Content-Encoding" header of value `a_encoding'.
put_content_language (a_lang: READABLE_STRING_8)
-- Put "Content-Language" header of value `a_lang'.
put_content_length (a_length: INTEGER_32)
-- Put "Content-Length:" + length `a_length'.
put_content_transfer_encoding (a_mechanism: READABLE_STRING_8)
-- Put "Content-Transfer-Encoding" header with `a_mechanism'
put_content_type (a_content_type: READABLE_STRING_8)
-- Put header line "Content-Type:" + type `a_content_type'
put_content_type_with_charset (a_content_type: READABLE_STRING_8; a_charset: READABLE_STRING_8)
-- Put content type `a_content_type' with `a_charset' as "charset" parameter.
put_content_type_with_name (a_content_type: READABLE_STRING_8; a_name: READABLE_STRING_8)
-- Put content type `a_content_type' with `a_name' as "name" parameter.
put_content_type_with_parameters (a_content_type: READABLE_STRING_8; a_params: detachable ARRAY [TUPLE [name: READABLE_STRING_8; value: READABLE_STRING_8]])
-- Put header line "Content-Type:" + type `a_content_type' and extra paramaters `a_params'
put_transfer_encoding (a_encoding: READABLE_STRING_8)
-- Put "Transfer-Encoding" header with `a_encoding' value.
put_transfer_encoding_binary
-- Put "Transfer-Encoding: binary" header
put_transfer_encoding_chunked
-- Put "Transfer-Encoding: chunked" header
feature -- Content-type helpers
put_content_type_application_javascript
put_content_type_application_json
put_content_type_application_pdf
put_content_type_application_x_www_form_encoded
put_content_type_application_zip
put_content_type_image_gif
put_content_type_image_jpg
put_content_type_image_png
put_content_type_image_svg_xml
put_content_type_message_http
put_content_type_multipart_alternative
put_content_type_multipart_encrypted
put_content_type_multipart_form_data
put_content_type_multipart_mixed
put_content_type_multipart_related
put_content_type_multipart_signed
put_content_type_text_css
put_content_type_text_csv
put_content_type_text_html
put_content_type_text_javascript
put_content_type_text_json
put_content_type_text_plain
put_content_type_text_xml
put_content_type_utf_8_text_plain
feature -- Cookie
put_cookie (key, value: READABLE_STRING_8; expiration, path, domain: detachable READABLE_STRING_8; secure, http_only: BOOLEAN)
-- Set a cookie on the client's machine
-- with key 'key' and value 'value'.
-- Note: you should avoid using "localhost" as `domain' for local cookies
-- since they are not always handled by browser (for instance Chrome)
require
make_sense: (key /= Void and value /= Void) and then (not key.is_empty and not value.is_empty)
domain_without_port_info: domain /= Void implies domain.index_of (':', 1) = 0
put_cookie_with_expiration_date (key, value: READABLE_STRING_8; expiration: DATE_TIME; path, domain: detachable READABLE_STRING_8; secure, http_only: BOOLEAN)
-- Set a cookie on the client's machine
-- with key 'key' and value 'value'.
require
make_sense: (key /= Void and value /= Void) and then (not key.is_empty and not value.is_empty)
feature -- Cross-Origin Resource Sharing
put_access_control_allow_all_origin
-- Put "Access-Control-Allow-Origin: *" header.
put_access_control_allow_credentials (b: BOOLEAN)
-- Indicates whether or not the response to the request can be exposed when the credentials flag is true.
-- When used as part of a response to a preflight request, this indicates whether or not the actual request can be made using credentials.
-- Note that simple GET requests are not preflighted, and so if a request is made for a resource with credentials,
-- if this header is not returned with the resource, the response is ignored by the browser and not returned to web content.
-- ex: Access-Control-Allow-Credentials: true | false
put_access_control_allow_headers (a_headers: READABLE_STRING_8)
-- Put "Access-Control-Allow-Headers" header. with value `a_headers'
-- Used in response to a preflight request to indicate which HTTP headers can be used when making the actual request.
-- ex: Access-Control-Allow-Headers: <field-name>[, <field-name>]*
put_access_control_allow_iterable_headers (a_fields: ITERABLE [READABLE_STRING_8])
-- Put "Access-Control-Allow-Headers" header. with value `a_headers'
-- Used in response to a preflight request to indicate which HTTP headers can be used when making the actual request.
-- ex: Access-Control-Allow-Headers: <field-name>[, <field-name>]*
put_access_control_allow_methods (a_methods: ITERABLE [READABLE_STRING_8])
-- If `a_methods' is not empty, put `Access-Control-Allow-Methods' header with list `a_methods' of methods
-- `a_methods' specifies the method or methods allowed when accessing the resource.
-- This is used in response to a preflight request.
-- ex: Access-Control-Allow-Methods: <method>[, <method>]*
put_access_control_allow_origin (a_origin: READABLE_STRING_8)
-- Put "Access-Control-Allow-Origin: " + `a_origin' header.
-- `a_origin' specifies a URI that may access the resource
feature -- Date
put_current_date
-- Put current date time with "Date" header
put_date (a_date: READABLE_STRING_8)
-- Put "Date: " header
put_last_modified (a_utc_date: DATE_TIME)
-- Put UTC date time `dt' with "Last-Modified" header
put_utc_date (a_utc_date: DATE_TIME)
-- Put UTC date time `a_utc_date' with "Date" header
-- using RFC1123 date formating.
feature -- Header change: deferred
add_header (h: READABLE_STRING_8)
-- Add header `h'
-- if it already exists, there will be multiple header with same name
-- which can also be valid
require
h_not_empty: h /= Void and then not h.is_empty
put_header (h: READABLE_STRING_8)
-- Add header `h' or replace existing header of same header name
require
h_not_empty: h /= Void and then not h.is_empty
feature -- Header change: general
add_header_key_value (a_header_name, a_value: READABLE_STRING_8)
-- Add header `a_header_name:a_value'.
-- If it already exists, there will be multiple header with same name
-- which can also be valid
ensure
added: has_header_named (a_header_name)
force (a_value: detachable READABLE_STRING_8; a_header_name: READABLE_STRING_8)
-- Put header `a_header_name:a_value' or replace existing header of name `a_header_name'.
put_header_key_value (a_header_name, a_value: READABLE_STRING_8)
-- Add header `a_header_name:a_value', or replace existing header of same header name/key
ensure
added: has_header_named (a_header_name)
put_header_key_values (a_header_name: READABLE_STRING_8; a_values: ITERABLE [READABLE_STRING_8]; a_separator: detachable READABLE_STRING_8)
-- Add header `a_header_name: a_values', or replace existing header of same header values/key.
-- Use Comma_space as default separator if `a_separator' is Void or empty.
ensure
added: has_header_named (a_header_name)
feature -- Method related
put_allow (a_methods: ITERABLE [READABLE_STRING_8])
-- If `a_methods' is not empty, put `Allow' header with list `a_methods' of methods
feature -- Others
put_cache_control (a_cache_control: READABLE_STRING_8)
-- Put "Cache-Control" header with value `a_cache_control'
put_expires (a_seconds: INTEGER_32)
-- Put "Expires" header to `a_seconds' seconds
put_expires_date (a_utc_date: DATE_TIME)
-- Put "Expires" header with UTC date time value
-- formatted following RFC1123 specification.
put_expires_string (a_expires: STRING_8)
-- Put "Expires" header with `a_expires' string value
put_pragma (a_pragma: READABLE_STRING_8)
-- Put "Pragma" header with value `a_pragma'
put_pragma_no_cache
-- Put "Pragma" header with "no-cache" a_pragma
feature -- Redirection
put_location (a_uri: READABLE_STRING_8)
-- Tell the client the new location `a_uri'
-- using "Location" header.
require
a_uri_valid: not a_uri.is_empty
put_refresh (a_uri: READABLE_STRING_8; a_timeout_in_seconds: INTEGER_32)
-- Tell the client to refresh page with `a_uri' after `a_timeout_in_seconds' in seconds
-- using "Refresh" header.
require
a_uri_valid: not a_uri.is_empty
end -- class HTTP_HEADER_MODIFIER
HTTP 1.1 Response Headers
There are four categories for response header fields:
- Control Data : Supply control data that supplements the status code, directs caching, or instructs the client where to go next.
- Age,Cache-Control,Expires,Date,Location,Retry-After,Vary,Warning.
- Validator: Validator header fields convey metadata about the selected representation. In responses to safe requests, validator fields describe the selected representation chosen by the origin server while handling the response.
- Authentication Challenges: Indicate what mechanisms are available for the client to provide authentication credentials in future requests.
- Response Context: Provide more information about the target resource for potential use in later requests.
Nav: Workbook :: Handling Requests: Header Fields :: Handling Cookies