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cURL

cURL is a computer software project providing a library and command-line tool for transferring data using various protocols. The cURL project produces two products, libcurl and cURL. It was first released in 1997.

curl is a command line tool for transferring data with URL syntax, supporting DICT, FILE, FTP, FTPS, Gopher, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, POP3, POP3S, RTMP, RTSP, SCP, SFTP, SMTP, SMTPS, Telnet and TFTP. curl supports SSL certificates, HTTP POST, HTTP PUT, FTP uploading, HTTP form based upload, proxies, cookies, user+password authentication (Basic, Digest, NTLM, Negotiate, kerberos…), file transfer resume, proxy tunneling and a busload of other useful tricks.

Working with HTTP from the command-line is a valuable skill for HTTP architects and API designers to have. The cURL library and curl command give you the ability to design a Request, put it on the pipe, and explore the Response. The downside to the power of curl is how much breadth its options cover. Running curl --help spits out 150 different flags and options. This article demonstrates nine basic, real-world applications of curl.

In this tutorial we’ll use the httpkit echo service as our end point. The echo server’s Response is a JSON representation of the HTTP request it receives.

Make a Request

Let’s start with the simplest curl command possible.

Request
curl http://echo.httpkit.com
Response
{
  "method": "GET",
  "uri": "/",
  "path": {
    "name": "/",
    "query": "",
    "params": {}
  },
  "headers": {
    "host": "echo.httpkit.com",
    "user-agent": "curl/7.24.0 ...",
    "accept": "*/*"
  },
  "body": null,
  "ip": "28.169.144.35",
  "powered-by": "http://httpkit.com",
  "docs": "http://httpkit.com/echo"
}

Just like that we have used curl to make an HTTP Request. The method, or “verb”, curl uses, by default, is GET. The resource, or “noun”, we are requestion is addressed by the URL pointing to the httpkit echo service, http://echo.httpkit.com.

You can add path and query string parameters right to the URL.

Request
curl http://echo.httpkit.com/path?query=string
Response
{ ...
  "uri": "/path?query=string",
  "path": {
    "name": "/path",
    "query": "?query=string",
    "params": {
      "query": "string"
    }
  }, ...
}

Set the Request Method

The curl default HTTP method, GET, can be set to any method you would like using the -X option. The usual suspects POST, PUT, DELETE, and even custom methods, can be specified.

Request
curl -X POST echo.httpkit.com
Response
{
    "method": "POST",
    ...
}

As you can see, the http:// protocol prefix can be dropped with curl because it is assumed by default. Let’s give DELETE a try, too.

Request
curl -X DELETE echo.httpkit.com
Response
{
    "method": "DELETE",
    ...
}

Set Request Headers

Request headers allow clients to provide servers with meta information about things such as authorization, capabilities, and body content-type. OAuth2 uses an Authorization header to pass access tokens, for example. Custom headers are set in curl using the -H option.

Request
curl -H "Authorization: OAuth 2c4419d1aabeec" 
     http://echo.httpkit.com
Response
{...
"headers": {
    "host": "echo.httpkit.com",
    "authorization": "OAuth 2c4419d1aabeec",
  ...},
...}

Multiple headers can be set by using the -H option multiple times.

Request
curl -H "Accept: application/json" 
     -H "Authorization: OAuth 2c3455d1aeffc" 
     http://echo.httpkit.com
Response
{ ...
  "headers": { ...
    "host": "echo.httpkit.com",
    "accept": "application/json",
    "authorization": "OAuth 2c3455d1aeffc" 
   }, ...
}

Send a Request Body

Many popular HTTP APIs today POST and PUT resources using application/json or application/xml rather than in an HTML form data. Let’s try PUTing some JSON data to the server.

Request
curl -X PUT 
     -H 'Content-Type: application/json' 
     -d '{"firstName":"Kris", "lastName":"Jordan"}'
     echo.httpkit.com
Response
{
   "method": "PUT", ...
   "headers": { ...
     "content-type": "application/json",
     "content-length": "40"
   },
   "body": "{"firstName":"Kris","lastName":"Jordan"}",
   ...
 }

Use a File as a Request Body

Escaping JSON/XML at the command line can be a pain and sometimes the body payloads are large files. Luckily, cURL’s @readfile macro makes it easy to read in the contents of a file. If we had the above example’s JSON in a file named “example.json” we could have run it like this, instead:

Request
curl -X PUT 
     -H 'Content-Type: application/json' 
     -d @example.json
     echo.httpkit.com

POST HTML Form Data

Being able to set a custom method, like POST, is of little use if we can’t also send a request body with data. Perhaps we are testing the submission of an HTML form. Using the -d option we can specify URL encoded field names and values.

Request
curl -d "firstName=Kris" 
     -d "lastName=Jordan" 
     echo.httpkit.com
Response
{
  "method": "POST", ...
  "headers": {
    "content-length": "30",
    "content-type":"application/x-www-form-urlencoded"
  },
  "body": "firstName=Kris&lastName=Jordan", ...
}

Notice the method is POST even though we did not specify it. When curl sees form field data it assumes POST. You can override the method using the -X flag discussed above. The “Content-Type” header is also automatically set to “application/x-www-form-urlencoded” so that the web server knows how to parse the content. Finally, the request body is composed by URL encoding each of the form fields.

POST HTML Multipart / File Forms

What about HTML forms with file uploads? As you know from writing HTML file upload form, these use a multipart/form-data Content-Type, with the enctype attribute in HTML. In cURL we can pair the -F option and the @readFile macro covered above.

Request
curl -F "firstName=Kris" 
     -F "publicKey=@idrsa.pub;type=text/plain" 
     echo.httpkit.com
Response
{
  "method": "POST",
  ...
  "headers": {
    "content-length": "697",
    "content-type": "multipart/form-data;
    boundary=----------------------------488327019409",
    ... },
  "body": "------------------------------488327019409rn
           Content-Disposition: form-data;
           name="firstName"rnrn
           Krisrn
           ------------------------------488327019409rn
           Content-Disposition: form-data;
           name="publicKey";
           filename="id_rsa.pub"rn
           Content-Type: text/plainrnrn
           ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAkq1lZYUOJH2
           ... more [a-zA-Z0-9]* ...
           naZXJw== krisjordan@gmail.comnrn
           ------------------------------488327019409
           --rn",
...}

Like with the -d flag, when using -F curl will automatically default to the POST method, the multipart/form-data content-type header, calculate length, and compose the multipart body for you. Notice how the @readFile macro will read the contents of a file into any string, it’s not just a standalone operator. The “;text/plain” specifies the MIME content-type of the file. Left unspecified, curl will attempt to sniff the content-type for you.

Test Virtual Hosts, Avoid DNS

Testing a virtual host or a caching proxy before modifying DNS and without overriding hosts is useful on occassion. With cURL just point the request at your host’s IP address and override the default Host header cURL sets up.

Request
curl -H "Host: google.com" 50.112.251.120
Response
{
  "method": "GET", ...
  "headers": {
    "host": "google.com", ...
  }, ...
}

View Response Headers

APIs are increasingly making use of response headers to provide information on authorization, rate limiting, caching, etc. With cURL you can view the headers and the body using the -i flag.

Request
curl -i echo.httpkit.com
Response
HTTP/1.1 200 OK
Server: nginx/1.1.19
Date: Wed, 29 Aug 2012 04:18:19 GMT
Content-Type: application/json; charset=utf-8
Content-Length: 391
Connection: keep-alive
X-Powered-By: http://httpkit.com

{
  "method": "GET",
  "uri": "/", ...
}

Shameless plug: Do you hack on REST API integrations or implementations? Wiretap is an HTTP debugger you can use to see every request and response between any client and HTTP API in real time. It’s entering private beta soon. Help test it!

on an Ubuntu system (probably Debian too)

$ sudo apt-get install php5-curl

The basic idea behind the cURL functions is that you initialize a cURL session using the curl_init(), then you can set all your options for the transfer via the curl_setopt(), then you can execute the session with the curl_exec() and then you finish off your session using the curl_close(). Here is an example that uses the cURL functions to fetch the example.com homepage into a file:

<?php

$ch = curl_init("http://example.iana.org/");
$fp = fopen("example_homepage.txt", "w");

curl_setopt($ch, CURLOPT_FILE, $fp);
curl_setopt($ch, CURLOPT_HEADER, 0);

curl_exec($ch);
curl_close($ch);
fclose($fp);
?>

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Ubuntu lamp

XAMPP is an easy to install Apache distribution containing MySQL, PHP and Perl. XAMPP is really very easy to install and to use – just download, extract and start.

This is to help people setup and install a LAMP (Linux-Apache-MySQL-PHP) server in Ubuntu, including Apache 2, PHP 5 and MySQL 4.1 or 5.0.

To install the default LAMP stack in Ubuntu 10.04 and above

First install tasksel…

 

$ sudo apt-get install tasksel

… and then the LAMP stack:

 

$ sudo tasksel install lamp-server

See Tasksel – be warned, only use tasksel to install tasks, not to remove them – see https://launchpad.net/bugs/574287
DO NOT UNCHECK ANY PACKAGES IN THE MENU WHICH APPEARS
You can leave your system in an unusable state.

Starting over: How to remove the LAMP stack

To remove the LAMP stack remove the following packages:

  • Note: This assumes you have no other programs that require any of these packages. You might wish to simulate this removal first, and only remove the packages that don’t cause removal of something desired.

 

apache2 apache2-mpm-prefork apache2-utils apache2.2-common libapache2-mod-php5 libapr1 libaprutil1 libdbd-mysql-perl libdbi-perl libnet-daemon-perl libplrpc-perl libpq5 mysql-client-5.5 mysql-common mysql-server mysql-server-5.5 php5-common php5-mysql

To also remove the debconf data, use the purge option when removing. To get rid of any configurations you may have made to apache, manually remove the /etc/apache2 directory once the packages have been removed.

You may also want to purge these packages:

mysql-client-core-5.5 mysql-server-core-5.5

 

Installing Apache 2

To only install the apache2 webserver, use any method to install:

 

apache2

It requires a restart for it to work:

 

$ sudo /etc/init.d/apache2 restart

or

 

$ sudo service apache2 restart

 

Checking Apache 2 installation

With your web browser, go to the URI http://localhost : if you read “It works!”, which is the content of the file /var/www/index.html , this proves Apache works.

 

Troubleshooting Apache

If you get this error:

apache2: Could not determine the server’s fully qualified domain name, using 127.0.0.1 for ServerName

then use a text editor such as “sudo nano” at the command line or “gksudo gedit” on the desktop to create a new file,

$ sudo nano /etc/apache2/conf.d/fqdn

or

$ gksu "gedit /etc/apache2/conf.d/fqdn"

then add

ServerName localhost

to the file and save. This can all be done in a single command with the following:

$ echo "ServerName localhost" | sudo tee /etc/apache2/conf.d/fqdn

 

Virtual Hosts

Apache2 has the concept of sites, which are separate configuration files that Apache2 will read. These are available in /etc/apache2/sites-available. By default, there is one site available called default this is what you will see when you browse to http://localhost or http://127.0.0.1. You can have many different site configurations available, and activate only those that you need.

As an example, we want the default site to be /home/user/public_html/. To do this, we must create a new site and then enable it in Apache2.

To create a new site:

  • Copy the default website as a starting point. sudo cp /etc/apache2/sites-available/default /etc/apache2/sites-available/mysite 
  • Edit the new configuration file in a text editor “sudo nano” on the command line or “gksudo gedit”, for example: gksudo gedit /etc/apache2/sites-available/mysite
  • Change the DocumentRoot to point to the new location. For example, /home/user/public_html/
  • Change the Directory directive, replace <Directory /var/www/> to <Directory /home/user/public_html/>
  • You can also set separate logs for each site. To do this, change the ErrorLog and CustomLog directives. This is optional, but handy if you have many sites
  • Save the file

Now, we must deactivate the old site, and activate our new one. Ubuntu provides two small utilities that take care of this: a2ensite (apache2enable site) and a2dissite (apache2disable site).

 

$ sudo a2dissite default && sudo a2ensite mysite

Finally, we restart Apache2:

 

$ sudo /etc/init.d/apache2 restart

If you have not created /home/user/public_html/, you will receive an warning message

To test the new site, create a file in /home/user/public_html/:

 

$ echo '<b>Hello! It is working!</b>' > /home/user/public_html/index.html

Finally, browse to http://localhost/

 

Installing PHP 5

To only install PHP5. use any method to install the package

 

libapache2-mod-php5

Enable this module by doing

$ sudo a2enmod php5

which creates a symbolic link /etc/apache2/mods-enabled/php5 pointing to /etc/apache2/mods-availble/php5 .

Except if you use deprecated PHP code beginning only by “<?” instead of “<?php” (which is highly inadvisable), open, as root, the file /etc/php5/apache2/php.ini , look for the line “short_open_tag = On”, change it to “short_open_tag = Off” (not including the quotation marks) and add a line of comment (beginning by a semi-colon) giving the reason, the author and the date of this change. This way, if you later want some XML or XHTML file to be served as PHP, the “<?xml” tag will be ignored by PHP instead of being seen as a PHP code mistake.

Relaunch Apache 2 again:

 

$ sudo service apache2 restart

 

Checking PHP 5 installation

In /var/www , create a text file called “test.php”, grant the world (or, at least, Ubuntu user “apache”) permission to read it, write in it the only line: “<?php phpinfo(); ?>” (without the quotation marks) then, with your web browser, go to the URI “http://localhost/test.php“: if you can see a description of PHP5 configuration, it proves PHP 5 works with Apache.

 

Troubleshooting PHP 5

Does your browser ask if you want to download the php file instead of displaying it? If Apache is not actually parsing the php after you restarted it, install libapache2-mod-php5. It is installed when you install the php5 package, but may have been removed inadvertently by packages which need to run a different version of php.

If sudo a2enmod php5 returns “$ This module does not exist!”, you should purge (not just remove) the libapache2-mod-php5 package and reinstall it.

Be sure to clear your browser’s cache before testing your site again. To do this in Firefox 4: Edit → Preferences … Privacy → History: clear your recent history → Details : choose “Everything” in “Time range to clean” and check only “cache”, then click on “Clear now”.

Remember that, for Apache to be called, the URI in your web browser must begin with “http://“. If it begins with “file://“, then the file is read directly by the browser, without Apache, so you get (X)HTML and CSS, but no PHP. If you didn’t configure any host alias or virtual host, then a local URI begins with “http://localhost“, “http://127.0.0.1” or http://” followed by your IP number.

If the problem persists, check your PHP file authorisations (it should be readable at least by Ubuntu user “apache”), and check if the PHP code is correct. For instance, copy your PHP file, replace your whole PHP file content by “<?php phpinfo(); ?>” (without the quotation marks): if you get the PHP test page in your web browser, then the problem is in your PHP code, not in Apache or PHP configuration nor in file permissions. If this doesn’t work, then it is a problem of file authorisation, Apache or PHP configuration, cache not emptied, or Apache not running or not restarted. Use the display of that test file in your web browser to see the list of files influencing PHP behaviour.

 

php.ini development vs. production

After standard installation, php configuration file /etc/php5/apache2/php.ini is set so as “production settings” which means, among others, that no error messages are displayed. So if you e.g. make a syntax error in your php source file, apache server would return HTTP 500 error instead of displaying the php syntax error debug message.

If you want to debug your scripts, it might be better to use the “development” settings. Both development and production settings ini’s are located in /usr/share/php5/

/usr/share/doc/php5-common/examples/php.ini-development 

/usr/share/php5/php.ini-production

so you can compare them and see the exact differences.

To make the “development” settings active, just backup your original php.ini

sudo mv /etc/php5/apache2/php.ini /etc/php5/apache2/php.ini.bak

and create a symlink to your desired settings:

sudo cp -s /usr/share/doc/php5-common/examples/php.ini-development /etc/php5/apache2/php.ini

or you may of course also edit the /etc/php5/apache2/php.ini directly on your own, if you wish.

 

PHP in user directories

According to this blog, newer versions of Ubuntu do not have PHP enabled by default for user directories (your public_html folder). See the blog for instructions on how to change this back.

 

Installing MYSQL with PHP 5

Use any method to install

 

mysql-server libapache2-mod-auth-mysql php5-mysql

 

After installing PHP

You may need to increase the memory limit that PHP imposes on a script. Edit the /etc/php5/apache2/php.ini file and increase the memory_limit value.

 

After installing MySQL

 

Set mysql bind address

Before you can access the database from other computers in your network, you have to change its bind address. Note that this can be a security problem, because your database can be accessed by other computers than your own. Skip this step if the applications which require mysql are running on the same machine.

type:

$ sudo nano /etc/mysql/my.cnf

and change the line:

bind-address           = localhost

to your own internal ip address e.g. 192.168.1.20

bind-address           = 192.168.1.20

If your ip address is dynamic you can also comment out the bind-address line and it will default to your current ip.

If you try to connect without changing the bind-address you will recieve a “Can not connect to mysql error 10061”.

 

Set mysql root password

Before accessing the database by console you need to type:

$ mysql -u root

At the mysql console type:

$ mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('yourpassword');

A successful mysql command will show:

Query OK, 0 rows affected (0.00 sec)

Mysql commands can span several lines. Do not forget to end your mysql command with a semicolon.

Note: If you have already set a password for the mysql root, you will need to use:

$ mysql -u root -p

(Did you forget the mysql-root password? See MysqlPasswordReset.)

 

Create a mysql database

 

$ mysql> CREATE DATABASE database1;

 

Create a mysql user

For creating a new user with all privileges (use only for troubleshooting), at mysql prompt type:

$ mysql> GRANT ALL PRIVILEGES ON *.* TO 'yourusername'@'localhost' IDENTIFIED BY 'yourpassword' WITH GRANT OPTION;

For creating a new user with fewer privileges (should work for most web applications) which can only use the database named “database1”, at mysql prompt type:

$ mysql> GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, INDEX, ALTER, CREATE TEMPORARY TABLES, LOCK TABLES ON database1.* TO 'yourusername'@'localhost' IDENTIFIED BY 'yourpassword';

yourusername and yourpassword can be anything you like. database1 is the name of the database the user gets access to. localhost is the location which gets access to your database. You can change it to ‘%’ (or to hostnames or ip addresses) to allow connections from every location (or only from specific locations) to the database. Note, that this can be a security problem and should only be used for testing purposes!

To exit the mysql prompt type:

$ mysql> q

Since the mysql root password is now set, if you need to use mysql again (as the mysql root), you will need to use:

$ mysql -u root -p

and then enter the password at the prompt.

 

Backup-Settings

Please, let’s say something in which directories mysql stores the database information and how to configure a backup

 

Alternatively

There is more than just one way to set the mysql root password and create a database. For example mysqladmin can be used:

 

$ mysqladmin -u root -p password yourpassword

and

 

$ mysqladmin -u root -p create database1

mysqladmin is a command-line tool provided by the default LAMP install.

 

Phpmyadmin and mysql-workbench

All mysql tasks including setting the root password and creating databases can be done via a graphical interface using phpmyadmin or mysql-workbench.

To install one or both of them, first enable the universe repository

Use any method to install

 

phpmyadmin

 

Troubleshooting Phpmyadmin & mysql-workbench

If you get blowfish_secret error: Choose and set a phrase for cryptography in the file /etc/phpmyadmin/blowfish_secret.inc.php and copy the line (not the php tags) into the file /etc/phpmyadmin/config.inc.php or you will receive an error.

If you get a 404 error upon visiting http://localhost/phpmyadmin: You will need to configure apache2.conf to work with Phpmyadmin.

 

$ gksudo gedit /etc/apache2/apache2.conf

Include the following line at the bottom of the file, save and quit.

 

$ Include /etc/phpmyadmin/apache.conf

 

Alternative: install phpMyAdmin from source

See the phpMyAdmin page for instructions on how to install phpmyadmin from source:

 

Mysql-workbench

Mysql-workbench runs locally, on the desktop. Use any method to install

 

mysql-workbench

 

For more information

2.9.3. Securing the Initial MySQL Accounts from the MySQL Reference Manual is worth reading.

 

Edit Apache Configuration

You may want your current user to be the PHP pages administrator. To do so, edit the Apache configuration file :

$ gksudo "gedit /etc/apache2/envvars"

Search both the strings starting by “APACHE_RUN_USER” and “APACHE_RUN_GROUP”, and change the names to the current username and groupname you are using. Then you’ll need to restart Apache. (look at the next chapter concerning apache commands)

Configuration options relating specifically to user websites (accessed through localhost/~username) are in /etc/apache2/mods-enabled/userdir.conf.

 

Installing suPHP

suPHP is a tool for executing PHP scripts with the permissions of their owners. It consists of an Apache module (mod_suphp) and a setuid root binary (suphp) that is called by the Apache module to change the uid of the process executing the PHP interpreter.

Note: suPHP enforces, security and helps avoid file permission problems under development environments with several users editing the site files, but it also demands more memory and CPU usage, which can degrade your server performance under certain circumstances.

To only install suPHP. use any method to install the package

 

libapache2-mod-suphp

Enable this module by doing

 

sudo a2enmod suphp

then use a text editor such as “sudo nano” at the command line or “gksudo gedit” on the desktop to edit this file

 

sudo nano /etc/apache2/mods-available/php5.conf

or

 

gksu "gedit /etc/apache2/mods-available/php5.conf"

make a new empty line at the top of the content, then add

 

<Directory /usr/share>

make a new empty line at the bottom of the content, then add

 

</Directory>

save changes

For security reasons we need to specify to suPHP what are the document paths allowed to execute scripts, use a text editor such as “sudo nano” at the command line or “gksudo gedit” on the desktop to edit this file

 

sudo nano /etc/suphp/suphp.conf

or

 

gksu "gedit /etc/suphp/suphp.conf

find the value “docroot” and specify the document path of your site files, for example:

 

docroot=/var/www/

that value restrict script execution only to files inside “/var/www/”

 

docroot=/var/www/:${HOME}/public_html

that value restrict script execution only to files inside a custom home folder for each configured user inside “/var/www/:${HOME}/public_html”

for this tutorial we are going to use this value

 

docroot=/home/user/public_html/

which is the same Apache directory directive set before in this document

save changes

to restart Apache, type in your terminal

 

sudo /etc/init.d/apache2 restart

Now lets create a test script to see if suPHP is working correctly, in your terminal type

 

echo "<?php echo 'whoim = '.exec('/usr/bin/whoami');?>" | tee /home/user/public_html/whomi.php

that command creates a quick php test file to display the current user executing the script

open your browser and navigate to “localhost/whomi.php”, most likely the browser will show you a “500” server error, this is because suPHP does not allow too permissive file and folder permissions and also does not allow mixed file and folder ownership, to correct this type in your terminal

 

sudo find /home/user/public_html/ -type f -exec chmod 644 {} ;
sudo find /home/user/public_html/ -type d -exec chmod 755 {} ;
sudo chown user:group -R /home/user/public_html/

those commands enforce a secure and correct file and folder permission and also set a correct user and group ownership for all of them

Now open your browser and navigate to “localhost/whomi.php”, if everything went fine you should see the name of the file owner executing the script and not “www-data” unless you specified so

 

Run, Stop, Test, And Restart Apache

Use the following command to run Apache :

$ sudo /usr/sbin/apache2ctl start

To stop it, use :

$ sudo /usr/sbin/apache2ctl stop

To test configuration changes, use :

$ sudo /usr/sbin/apache2ctl configtest

Finally, to restart it, run :

$ sudo /usr/sbin/apache2ctl restart

Alternatively, you can use a graphical interface by installing Rapache or the simpler localhost-indicator.

Using Apache

You can access apache by typing 127.0.0.1 or http://localhost (by default it will be listening on port 80) in your browser address bar. By default the directory for apache server pages is /var/www . It needs root access in order to put files in. A way to do it is just starting the file browser as root in a terminal:

$ gksudo nautilus

or

if you want to make /var/www your own. (Use only for non-production web servers – this is not the most secure way to do things.)

$ sudo chown -R $USER:$USER /var/www

 

Status

To check the status of your PHP installation:

 $ gksudo "gedit /var/www/testphp.php"

and insert the following line

 <?php phpinfo(); ?>

View this page on a web browser at http://yourserveripaddress/testphp.php or http://localhost/testphp.php

 

Securing Apache

If you just want to run your Apache install as a development server and want to prevent it from listening for incoming connection attempts, this is easy to do.

$ gksudo "gedit /etc/apache2/ports.conf"
$ password:

Change ports.conf so that it contains:

Listen 127.0.0.1:80

Save this file, and restart Apache (see above). Now Apache will serve only to your home domain, http://127.0.0.1 or http://localhost.

 

Password-Protect a Directory

There are 2 ways to password-protect a specific directory. The recommended way involves editing  /etc/apache2/apache2.conf . (To do this, you need root access). The other way involves editing a .htaccess file in the directory to be protected. (To do this, you need access to that directory).

 

Password-Protect a Directory With .htaccess

See EnablingUseOfApacheHtaccessFiles

Warning: On at least some versions of Ubuntu, .htaccess files will not work by default. See EnablingUseOfApacheHtaccessFiles for help on enabling them.

 

thumbnails

If you direct your web browser to a directory (rather than a specific file), and there is no “index.html” file in that directory, Apache will generate an index file on-the-fly listing all the files and folders in that directory. Each folder has a little icon of a folder next to it.

To put a thumbnail of that specific image (rather than the generic “image icon”) next to each image file (.jpg, .png, etc.):

… todo: add instructions on how to do thumbnails here, perhaps using Apache::AutoIndex 0.08 or Apache::Album 0.95 …

 

Known problems

 

Skype incompatibility

Skype uses port 80 for incoming calls, and thus, may block Apache. The solution is to change the port in one of the applications. Usually, port 81 is free and works fine. To change the port number in Skype go to menu Tools > Options, then click on the Advanced tab, then in the box of the port for incoming calls write your preference.

 

Other Apache Options

 

Further Information

Posted on

Quick Response Code

QR code (abbreviated from Quick Response Code) is the trademark for a type of matrix barcode (or two-dimensional barcode) first designed for the automotive industry in Japan; a barcode is an optically machine-readable label that is attached to an item and that records information related to that item: The information encoded by a QR code may be made up of four standardized types (“modes”) of data (numeric, alphanumeric, byte / binary, Kanji) or, through supported extensions, virtually any type of data.[1]

The QR Code system has become popular outside the automotive industry due to its fast readability and greater storage capacity compared to standard UPC barcodes. Applications include product tracking, item identification, time tracking, document management, general marketing, and much more.[2]

A QR code consists of black modules (square dots) arranged in a square grid on a white background, which can be read by an imaging device (such as a camera) and processed using Reed-Solomon error correction until the image can be appropriately interpreted; data is then extracted from patterns present in both horizontal and vertical components of the image.[2]

PHP QR Code is open source (LGPL) library for generating QR Code, 2-dimensional barcode. Based on libqrencode C library, provides API for creating QR Code barcode images (PNG, JPEG thanks to GD2). Implemented purely in PHP, with no external dependencies (except GD2 if needed).

Some of library features includes:

  • Supports QR Code versions (size) 1-40
  • Numeric, Alphanumeric, 8-bit and Kanji encoding. (Kanji encoding was not fully tested, if you are japan-encoding enabled you can contribute by verifing it 🙂 )
  • Implemented purely in PHP, no external dependencies except GD2
  • Exports to PNG, JPEG images, also exports as bit-table
  • TCPDF 2-D barcode API integration
  • Easy to configure
  • Data cache for calculation speed-up
  • Provided merge tool helps deploy library as a one big dependency-less file, simple to “include and do not wory”
  • Debug data dump, error logging, time benchmarking
  • API documentation
  • Detailed examples
  • 100% Open Source, LGPL Licensed
Posted on

The Eric Python IDE

Eric is a full featured Python and Ruby editor and IDE, written in python. It is based on the cross platform Qt gui toolkit, integrating the highly flexible Scintilla editor control. It is designed to be usable as everdays’ quick and dirty editor as well as being usable as a professional project management tool integrating many advanced features Python offers the professional coder. eric4 includes a plugin system, which allows easy extension of the IDE functionality with plugins downloadable from the net.

Current stable versions are eric4 based on Qt4 and Python 2 and eric5 based on Python 3 and Qt4.

http://ubuntuforums.org/showthread.php?t=1601218
sudo apt-get install libqt4-dev
install python3.2-dev (sudo apt-get install python3.2-dev)
Use Synaptic or Download it from here: http://www.riverbankcomputing.co.uk
1) build/install qscintilla
2) build/install sip
3) build/install PyQt
Python 3.2.3
Qt 4.8.1
PyQt 4.9.1
QScintilla 2.6.1

Python from Scratch