Send and Receive HTTP Messages - MATLAB & Simulink (original) (raw)

This example shows how to send a request to a server that involves redirection and might require digest authentication.

The sendRequest function automatically redirects and authenticates on the first request. For subsequent requests, you do not want to pay the cost of a redirect. To do this, sendRequest saves the cookies received on previous requests and reuses them for subsequent requests.

sendRequest illustrates the use of the history, the reuse of a custom HTTPOptions object to change the default timeout, and the use of saved credentials.

This example does not illustrate a robust, general-purpose mechanism for achieving these results. In particular, sendRequest returns all cookies received from a host in every subsequent message to that host, regardless of the domain, path, expiration, or other properties. sendRequest also does not save credentials or cookies across MATLAB® sessions. Nonetheless, sendRequest is adequate for many applications.

Create the sendRequest function from the following code.

function response = sendRequest(uri,request)

% uri: matlab.net.URI % request: matlab.net.http.RequestMessage % response: matlab.net.http.ResponseMessage

% matlab.net.http.HTTPOptions persists across requests to reuse previous % Credentials in it for subsequent authentications persistent options

% infos is a containers.Map object where: % key is uri.Host; % value is "info" struct containing: % cookies: vector of matlab.net.http.Cookie or empty % uri: target matlab.net.URI if redirect, or empty persistent infos

if isempty(options) options = matlab.net.http.HTTPOptions('ConnectTimeout',20); end

if isempty(infos) infos = containers.Map; end host = string(uri.Host); % get Host from URI try % get info struct for host in map info = infos(host); if ~isempty(info.uri) % If it has a uri field, it means a redirect previously % took place, so replace requested URI with redirect URI. uri = info.uri; end if ~isempty(info.cookies) % If it has cookies, it means we previously received cookies from this host. % Add Cookie header field containing all of them. request = request.addFields(matlab.net.http.field.CookieField(info.cookies)); end catch % no previous redirect or cookies for this host info = []; end

% Send request and get response and history of transaction. [response, ~, history] = request.send(uri, options); if response.StatusCode ~= matlab.net.http.StatusCode.OK return end

% Get the Set-Cookie header fields from response message in % each history record and save them in the map. arrayfun(@addCookies, history)

% If the last URI in the history is different from the URI sent in the original % request, then this was a redirect. Save the new target URI in the host info struct. targetURI = history(end).URI; if ~isequal(targetURI, uri) if isempty(info) % no previous info for this host in map, create new one infos(char(host)) = struct('cookies',[],'uri',targetURI); else % change URI in info for this host and put it back in map info.uri = targetURI; infos(char(host)) = info; end end

function addCookies(record)
    % Add cookies in Response message in history record
    % to the map entry for the host to which the request was directed.
    %
    ahost = record.URI.Host; % the host the request was sent to
    cookieFields = record.Response.getFields('Set-Cookie');
    if isempty(cookieFields)
        return
    end
    cookieData = cookieFields.convert(); % get array of Set-Cookie structs
    cookies = [cookieData.Cookie]; % get array of Cookies from all structs
    try
        % If info for this host was already in the map, add its cookies to it.
        ainfo = infos(ahost);
        ainfo.cookies = [ainfo.cookies cookies];
        infos(char(ahost)) = ainfo;
    catch
        % Not yet in map, so add new info struct.
        infos(char(ahost)) = struct('cookies',cookies,'uri',[]);
    end
end

end

Call the function.

request = matlab.net.http.RequestMessage; uri = matlab.net.URI('https://www.mathworks.com/products'); response = sendRequest(uri,request)

response = ResponseMessage with properties:

StatusLine: 'HTTP/1.1 200 OK' StatusCode: OK Header: [1×11 matlab.net.http.HeaderField] Body: [1×1 matlab.net.http.MessageBody] Completed: 0

Your response values might be different.

Send and Receive HTTP Messages - MATLAB & Simulink (original) (raw)

See Also