MATLAB: Can I perform basic authentication with URLREAD in MATLAB

MATLAB

I am using the URLREAD function to import a web page into MATLAB. However, to access the website I need to log on using basic authentication.

Best Answer

This functionality has been incorporated in Release 2013a (R2013a). See the R2013a documentation for URLREAD for more information. For previous product releases, read below for any possible workarounds:

The ability to use basic authentication with the URLREAD command is not available in MATLAB.

To work around this issue you can modify the URLREAD command to perform basic authentication. Basic Authentication is a specific authorization mechanism for web servers which is not secure. Not all web servers allow this type of authentication, so this work around may not apply to you.

The following work around has not been tested and therefore may require modification to get them to work in your situation. This implements a hard coded username and passwords into a copy of the URLREAD function. You will need to understand the basic authentication scheme in order to apply this workaround. References for more information are listed below.

1. Save a copy of the file $MATLABROOT\toolbox\matlab\iofun\urlread.m as $MATLABROOT\toolbox\matlab\iofun\urlread_basicauth.m (where $MATLABROOT is the MATLAB root directory on your machine, as returned by typing:

matlabroot

at the MATLAB command prompt.)

2. Open the file urlread_basicauth and add a line to add the basic authentication property to the URL connection. Around line 68 you should see the following section of code

[urlConnection,errorid,errormsg] = urlreadwrite(mfilename,urlChar);
if isempty(urlConnection)
      if catchErrors, return
      else error(errorid,errormsg);
      end
end

Imediately after this add the following code and save the changes.

urlConnection.setRequestProperty( ...
      'Authorization','Basic YWRtaW46YWRtaW4=');

3. Execute the following command at the MATLAB command prompt

rehash toolboxcache

4. Determine the encoded user name and password required for your authentication. Then subsitute your encoded username and password for "YWRtaW46YWRtaW4=" in code added in step 2. The encoding scheme is explained here: (following the link to "base-64" for more details)

http://en.wikipedia.org/wiki/Basic_authentication_scheme

Related Solutions

MATLAB: Do I get the error “Error downloading URL” when trying to open an FTP URL that needs a password in MATLAB 7.8 (R2009a)

The problem is caused by using an opening square bracket "[" in the password. A closing square bracket "]" would lead to the same error. The ability to automatically encode usernames or passwords for servers is not available in MATLAB.

To work around this issue, you can use Java functionality to URL-encode the password (or the username if needed) as follows:

urlread(['ftp://username:' char(java.net.URLEncoder.encode('mypass12{+[34')) '@ftp.dummyserver.com/'])

Keep in mind that the format of the URL should be:

<ftp://username:password@servername>

Do not encode the colon ":" between the username and the password.

MATLAB: How to use the IMREAD function with a URL that requires basic authentication in MATLAB

The ability to use basic authentication with the IMREAD command for a URL is not available in MATLAB. The IMREAD function internally uses the URLWRITE to create a image file. Hence as a workaround, you can try to modify the URLWRITE command to perform basic authentication. Basic Authentication is a specific authorization mechanism for web servers which is not secure. Not all web servers allow this type of authentication, so this work around may not apply to you.

The following workaround has not been tested and therefore may require modification to get them to work in your situation. This implements a hard coded username and passwords into a copy of the URLWRITE function. You will need to understand the basic authentication scheme in order to apply this workaround.

References for more information are listed below.

1. Save a copy of the file $MATLABROOT\toolbox\matlab\iofun\urlwrite.m as

$MATLABROOT\toolbox\matlab\iofun\urlwrite_basicauth.m (where $MATLABROOT is the MATLAB root

directory on your machine, as returned by typing:

 
matlabroot

at the MATLAB command prompt.)

2. Open the file urlwrite_basicauth and add a line to add the basic authentication property to the URL

connection. Around line 76 you should see the following section of code:

 
% Create a urlConnection.
[urlConnection,errorid,errormsg] = urlreadwrite(mfilename,urlChar);
if isempty(urlConnection)
    if catchErrors, return
    else error(errorid,errormsg);
    end
end

Immediately after this add the following code and save the changes.

 
urlConnection.setRequestProperty( 'Authorization','Basic YWRtaW46YWRtaW4=');

3. Execute the following command at the MATLAB command prompt

 
rehash toolboxcache

https://en.wikipedia.org/wiki/Basic_authentication_scheme

5. Now save a copy of the file $MATLABROOT\toolbox\matlab\imagesci\imread.m as

$MATLABROOT\toolbox\matlab\imagesci\imread_basicauth.m

6. Open the file imread_basicauth and replace the that uses the URLWRITE function with URLWRITE_BASICAUTH. Around line 338 you should see the following line of code:

filename = urlwrite(filename, tempname);

Replace this with :

filename = urlwrite_basicauth(filename, tempname);

Best Answer

Related Solutions

MATLAB: Do I get the error “Error downloading URL” when trying to open an FTP URL that needs a password in MATLAB 7.8 (R2009a)

MATLAB: How to use the IMREAD function with a URL that requires basic authentication in MATLAB

Related Question