tntnet.pdf

Tntnet users guide

Authors: Tommi Mäkitalo, Andreas Welchlin

Tntnet users guide

Table of contents

Concept....................................................................................................................................... 3

Installing Tntnet.......................................................................................................................... 3

Create a simple application with Tntnet......................................................................................3

C++-content (processing, expressions, conditional expressions)............................................... 4

Query-arguments (scalar/vector, untyped/typed, default-value)................................................. 4

Components................................................................................................................................ 5

Component-parameters............................................................................................................... 5

Returning from components........................................................................................................6

Calling components (dynamic/static)..........................................................................................6

Calling components from c++.....................................................................................................7

Include ecpp-files........................................................................................................................ 7

Declaring subcomponents........................................................................................................... 8

Passing parameters to components..............................................................................................8

Defining scoped variables........................................................................................................... 9

14.1

Lifetime.................................................................................................................................. 9

14.2

Scope.................................................................................................................................... 10

Cookies......................................................................................................................................11

Component attributes................................................................................................................ 12

Configuration............................................................................................................................ 12

Accessing configuration variables............................................................................................ 13

Logging..................................................................................................................................... 14

Exception handling................................................................................................................... 14

Savepoints................................................................................................................................. 14

Binary content........................................................................................................................... 15

Upload....................................................................................................................................... 15

HTTP-Auth............................................................................................................................... 16

Using c++-classes..................................................................................................................... 16

Creating stand alone web applications...................................................................................... 17

Some notes about multi threading.............................................................................................18

Tntnet users guide

1 Concept

Tntnet is a application server for web applications written in c++. A web

application in tntnet is written with a template-language, which embeds c++-

processing-instructions in html-pages. You can use external classes or

libraries in these pages. That way programmers can concentrate on the html-

result, when creating content and put processing in c++-classes.

Applications written with the template-language called ecpp are compiled into

c++-classes and linked into a dynamically loaded shared library. This is done

at compile-time – not at runtime, like other template-systems often do. On

runtime there is no compiler needed.

2 Installing Tntnet

Tntnet runs on Linux/Unix. You need a c++-compiler to compile Tntnet and

also to compile your web applications. As a prerequisite cxxtools (which is

available through the Tntnet-homepage http://www.tntnet.org) is needed.

Cxxtools is a collection of useful c++-classes.

To install tntnet you have to:

1. install cxxtools

2. unpack the sources with “tar xzf tntnet-version.tar.gz”

3. cd to the source-directory “cd tntnet-version.tar.gz”

4. run “./configure”

5. run “make”

6. run “make install”

This installs: The application server and tools for

1. tntnet – the web application server

2. ecppc – the ecpp-compiler

3. ecppl – the ecpp-language-extractor for internationalization

4. ecppll – the ecpp-language-linker for internationalization

5. some shared libraries

6. tntnet-config – a script, which gives you information about the installed

Tntnet and helps you setting up a simple project.

3 Create a simple application with Tntnet

The simplest way to create a tntnet-application is to use the tntnet-config-

script. Just run “tntnet-config –project=projectname”. This creates a directory

with the name of the project and:

1. projectname.ecpp – your first ecpp-file

2. Makefile – a simple makefile to build the application

3. tntnet.conf – a basic configuration file for tntnet

Tntnet users guide

4. tntnet.properties – a basic configuration file for logging-configuration

It used to be necessary to use a valid C++-class name as a project name,

since it was used as a class name internally. This is not true for tntnet 2.0 any

more.

To build the project, change to the directory and run “make”. This runs the

necessary steps to create a running application. You get a shared library

projectname.so, which contains the web application. To run it enter “tntnet

tntnet.conf” and navigate your browser to http://localhost:8000/projectname.

You get a simple Web-page.

4 C++-content (processing, expressions, conditional

expressions)

There are some simple tags, with which you can embed c++-content into the

page. The most important are processing-tags and output-tags.

With processing-tags you insert c++-code into the page, which is processed

on runtime. There are 3 alternatives to insert code:

The most verbose version is <%cpp> ...some c++-code... </%cpp> . A newline

after </%cpp> is ignored.

<{ starts an inline-block, which is terminated by }> . A newline after the

closing tag is not ignored, but passed to the browser.

The character '%' in the first column starts also c++-code until the end of

line.

A backslash disables the interpretation of the next character.

You can embed the result of a c++-expression with <$ expr $> into the html-

code. It is printed into the page. The type of the expression needs to have a

output-operator for std::ostream. The output is automatically translated into

html. Characters with special meaning in html are printed as their html entity

counterparts.

Often you need to print something depending on a condition. You can put a if-

statement around it. As a shortcut there is a special tag <? cond ? output ?> .

“cond” is evaluated as a c++-expression. If the result of this expression is

true, output is printed. The output is translated like <$...$> .

Another useful tag is <# ... #> , which is just a comment. The content is

skipped by the ecpp-compiler.

In C++-mode reply.out() returns a std::ostream , which writes text to the html-

page. reply.sout() returns a std::ostream , which escapes characters with special

meaning in html before writing to the page.

5 Query-arguments (scalar/vector, untyped/typed, default-

value)

Web-applications need to interact with the user. Therefore they send a html-

form to the user. After the user submits the form, the application needs to

Tntnet users guide

interpret the content of the form.

To support this, ecpp has a tag: <%args>...</%args> . Between this pair you

define the arguments of the form. Each argument is terminated with ';'. Ecpp

generates c++-variables of type std::string, containing the content of the

form.

You can precede arguments with a c++-type to convert the parameter

automatically into this type. This is done using the input-operator of

std::istream.

Since tntnet 2.0 a parameter defined with the type bool is interpretation as

true for all non empty strings. This makes it easy to check, if a specific submit

button was pressed.

Ecpp supports multiple input-tags with the same name, e.g. multiple

checkboxes or select-tag with attribute multiple . By appending [] to your

argument a std::vector and a typedef will be generated. Writing name[] will be

compiled to a typedef name_type and a vector name .

Single arguments can have a default value using the syntax variable =

default_value; .

Examples:

<%args>

name;

street;

city = “New York”;

int age; // content of text-input is converted to int

bool button1; // true, if the submit button with name “button1” was

used for

// submission

int sport[]; // multiple checkboxes with the same name

</%args>

<# use the vector like this: #>

% for (sport_type::const_iterator it = sport.begin(); it !=

sport.end(); ++it) {

<$ *it $>

% }

6 Components

Ecpp-pages are called components . They are identified by their name. The

name is composed of the local-name and the library-name divided with '@'.

The local name is by default the filename of the ecpp file without path and

extension, but may be changed to whatever needed by passing a name using

-n to the ecpp compiler ecppc. The -n switch can be used to pass full path

names as component names.

Components, which are called by Tntnet are called top-level-components.

Components can contain internal subcomponents . The subcomponent-name

is appended to the class-name divided by a dot. Subcomponents can't be

called directly from tntnet but only explicitly using a component call.

Examples are:

mycomp@app

Tntnet users guide

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