/ 
Outthentic-DSL-0.1.0
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/ Outthentic::DSL

NAME

Outthentic::DSL

SYNOPSIS

Language to validate text output.

Install

cpanm Outthentic::DSL

Informal introduction

Alternative outthentic dsl introduction could be found here

Glossary

Input text

An arbitrary, often unstructured text being verified. It could be any text.

Examples:

  • html code

  • xml code

  • json

  • plain text

  • emails :-)

  • http headers

  • another program languages code

Outthentic dsl

  • Is a language to verify arbitrary plain text

  • Outthentic dsl is both imperative and declarative language

Declarative way

You define rules ( check expressions ) to describe expected content.

Imperative way

You define a process of verification using custom perl code ( validators, generators, code expressions ).

dsl code

A program code written on outthentic dsl language to verify text input.

Search context

Verification process is carried out in a given context.

But default search context is the same as original input text stream.

Search context could be however changed in some conditions.

dsl parser

dsl parser is the program which:

  • parses dsl code

  • parses text input

  • verifies text input ( line by line ) against check expressions ( line by line )

Verification process

Verification process consists of matching lines of text input against check expressions.

This is schematic description of the process:

For every check expression in check expressions list.
    Mark this check step as in unknown state.
    For every line in input text.
        Does line match check expression? Check step is marked as succeeded.
        Next line.
    End of loop.
    Is this check step marked in unknown state? Mark this check step as in failed state.  
    Next check expression.
End of loop.
Are all check steps succeeded? Input text is verified.
Vise versa - input text is not verified.

A final presentation of verification results should be implemented in a certain client using parser api and not being defined at this scope.

For the sake of readability a fake results presentation layout is used in this document.

Parser API

Outthentic::DSL provides program api for client applications:

use Test::More qw{no_plan};

use Outthentic::DSL;

my $outh = Outthentic::DSL->new('input_text');

$outh->validate('/file/with/check/expressions/','input text');


for my $r ( @{$outh->results}){
    ok($r->{status}, $r->{message}) if $r->{type} eq 'check_expression';
    diag($r->{message}) if $r->{type} eq 'debug';

}

Methods list:

new

This is constructor, create Outthentic::DSL instance.

Obligatory parameters is:

  • input text string

Optional parameters is passed as hashref:

  • matchl - truncate matching strings to {matchl} bytes

Default value is `40'

  • debug_mod - enable debug mode

    • Possible values is 0,1,2,3.

    • Set to 1 or 2 or 3 if you want to see some debug information in validation results.

    • Increasing debug_mod value means more low level information appeared.

    • Default value is `0' - means do not create debug messages.

validate

Perform verification process.

Obligatory parameter is:

  • a path to file with dsl code

results

Returns validation results as arrayref containing { type, status, message } hashrefs.

Outthentic clients

Client is a external program using dsl API. Existed outthentic clients:

  • swat - web application testing tool

  • outthentic - generic testing tool

More clients wanted :) , please write me if you have one!

dsl code syntax

Outthentic dsl code comprises following basic entities:

  • Check expressions:

    • plain strings

    • regular expressions

    • text blocks

    • within expressions

    • range expressions

    • validator expressions

  • Comments

  • Blank lines

  • Perl expressions

  • Generator expressions

Check expressions

Check expressions define patterns to match input text stream.

Here is a simple example:

Input text:

HELLO
HELLO WORLD
My birth day is: 1977-04-16

Dsl code:

HELLO
regexp: \d\d\d\d-\d\d-\d\d

Results:

+--------+------------------------------+
| status | message                      |
+--------+------------------------------+
| OK     | matches "HELLO"              |
| OK     | matches /\d\d\d\d-\d\d-\d\d/ |
+--------+------------------------------+

There are two basic types of check expressions:

Plain text expressions

Plain text expressions are just a lines should be included at input text stream.

Dsl code:

I am ok
HELLO Outthentic

Input text:

I am ok , really
HELLO Outthentic !!!

Result - verified

Plain text expressions are case sensitive:

Input text:

I am OK

Result - not verified

Regular expressions

Similarly to plain text matching, you may require that input lines match some regular expressions:

Dsl code:

regexp: \d\d\d\d-\d\d-\d\d # date in format of YYYY-MM-DD
regexp: Name: \w+ # name
regexp: App Version Number: \d+\.\d+\.\d+ # version number

Input text:

2001-01-02
Name: outthentic
App Version Number: 1.1.10

Result - verified

One or many?

Parser does not care about how many times a given check expression is matched in input text.

If at least one line in a text match the check expression - this check is considered as succeeded.

Parser accumulate all matching lines for given check expression, so they could be processed.

Input text:

1 - for one
2 - for two
3 - for three       

regexp: (\d+) for (\w+)
code: for my $c( @{captures()}) {  print $c->[0], "/", $c->[1], "\n"}

Output:

1/one
2/two
3/three

See "captures" section for full explanation of a captures mechanism:

Comments, blank lines and text blocks

Comments and blank lines don't impact verification process but one could use them to improve code readability.

Comments

Comment lines start with `#' symbol, comments chunks are ignored by parser.

Dsl code:

# comments could be represented at a distinct line, like here
The beginning of story
Hello World # or could be added for the existed expression to the right, like here

Blank lines

Blank lines are ignored as well.

Dsl code:

# every story has the beginning
The beginning of a story
# then 2 blank lines


# end has the end
The end of a story

But you can't ignore blank lines in a `text block' context ( see `text blocks' subsection ).

Use `:blank_line' marker to match blank lines.

Dsl code:

# :blank_line marker matches blank lines
# this is especially useful
# when match in text blocks context:

begin:
    this line followed by 2 blank lines
    :blank_line
    :blank_line
end:

Text blocks

Sometimes it is very helpful to match against a `sequence of lines' like here.

Dsl code:

# this text block
# consists of 5 strings
# going consecutive

begin:
    # plain strings
    this string followed by
    that string followed by
    another one
    # regexps patterns:
    regexp: with (this|that)
    # and the last one in a block
    at the very end
end:

Input text:

this string followed by
that string followed by
another one string
with that string
at the very end.

Result - verified

Input text:

that string followed by
this string followed by
another one string
with that string
at the very end.

Result - not verified

`begin:' `end:' markers decorate `text blocks' content.

Markers should not be followed by any text at the same line.

Don't forget to close the block ...

Be aware if you leave "dangling" `begin:' marker without closing `end': somewhere else parser will remain in a `text block' mode till the end of the file, which is probably not you want:

Dsl code:

    begin:
        here we begin
        and till the very end of test

        we are in `text block` mode

Perl expressions

Perl expressions are just a pieces of Perl code to get evaled during parsing process.

This is how it works.

Dsl code:

# Perl expression 
# between two check expressions
Once upon a time
code: print "hello I am Outthentic"
Lived a boy called Outthentic

Output:

hello I am Outthentic

Internally once dsl code gets parsed it is "turned" into regular Perl code:

execute_check_expression("Once upon a time");
eval 'print "Lived a boy called Outthentic"';
execute_check_expression("Lived a boy called Outthentic");

One of the use case for Perl expressions is to store `captures' data.

Dsl code:

regexp: my name is (\w+) and my age is (\d+)
code: $main::data{name} = capture()->[0]; $main::data{age} = capture()->[1]; 
code: print $data->{name}, "\n";
code: print $data->{age}, "\n";

Input text:

my name is Alexey and my age is 38

Output:

Alexey
38

Additional comments on perl expressions:

Validators

Validator expressions like Perl expressions are just a piece of Perl code.

Validators start with `validator:' marker

A Perl code inside validator block should return array reference. Once code is executed a returned array structure treated as:

  • first element - is a status number ( perl true or false )

  • second element - is a helpful message

Validators a kind of check expressions with check logic expressed in validator code.

Examples.

Dsl code:

# this is always true
validator: [ 10>1 , 'ten is bigger then one' ]

# and this is not
validator: [ 1>10, 'one is bigger then ten'  ]

# this one depends on previous check
regexp: credit card number: (\d+)
validator: [ captures()->[0]-[0] == '0101010101', 'I know your secrets!'  ]


# and this could be any
validator: [ int(rand(2)) > 1, 'I am lucky!'  ]

Validators are very efficient when gets combined with `captures expressions'

This is a simple example.

Input text:

# my family ages list
alex    38
julia   32
jan     2

Dsl code:

# let's capture name and age chunks
regexp: /(\w+)\s+(\d+)/

validator: <<CODE
my $total=0;                        
for my $c (@{captures()}) {         
    $total+=$c->[0];                
}                                   
[ ( $total == 72 ), "total age" ] 

CODE

Generators

Generators is the way to generate new outthentic entries on the fly.

Generator expressions like Perl expressions are just a piece of Perl code.

The only requirement for generator code - it should return reference to array of strings.

Strings in array returned by generator code represent a new outthentic entities.

A new outthentic entries are passed back to parser and executed immediately.

Generators expressions start with `:generator' marker.

Here is simple example.

Dsl code:

# original check list

Say
HELLO
 
# this generator creates 3 new check expressions:

generator: [ qw{ say hello again } ]

New dsl code:

# final check list:

Say
HELLO
say
hello
again

Here is more complicated example.

Dsl code:

# this generator generates
# comment lines
# and plain string check expressions:

generator: <<CODE    
my %d = { 'foo' => 'foo value', 'bar' => 'bar value' };     
[ map  { ( "# $_", "$data{$_}" )  } keys %d ]
CODE

New dsl code:

# foo
foo value
# bar
bar value

Generators could produce not only check expressions but validators, perl expressions and ... generators.

This is fictional example.

Input Text:

A
AA
AAA
AAAA
AAAAA

Dsl code:

generator:  <<CODE
sub next_number {                       
    my $i = shift;                       
    $i++;                               
    return [] if $i>=5;                 
    [                                   
        'regexp: ^'.('A' x $i).'$'      
        "generator: next_number($i)"     
    ]  
}
CODE

Result - verified

Multiline expressions

Multilines in check expressions

When parser parses check expressions it does it in a single line mode :

  • a check expression is always single line string

  • input text is parsed in line by line mode, thus every line is validated against a single line check expression

Example.

# Input text

Multiline
string
here

Dsl code:

# check list
# consists of
# single line entries

Multiline
string
here
regexp: Multiline \n string \n here

Results:

+--------+---------------------------------------+
| status | message                               |
+--------+---------------------------------------+
| OK     | matches "Multiline"                   |
| OK     | matches "string"                      |
| OK     | matches "here"                        |
| FAIL   | matches /Multiline \n string \n here/ |
+--------+---------------------------------------+

Use text blocks if you want to represent multiline checks.

Multilines in perl expressions, validators and generators

Perl expressions, validators and generators could contain multilines expressions

There are two ways to write multiline expressions:

  • using \ delimiters to split multiline string to many chunks

  • using HERE documents expressions

Back slash delimiters

`\' delimiters breaks a single line text on a multi lines.

Example:

# What about to validate stdout
# With sqlite database entries?

generator:                                                          \

use DBI;                                                            \
my $dbh = DBI->connect("dbi:SQLite:dbname=t/data/test.db","","");   \
my $sth = $dbh->prepare("SELECT name from users");                  \
$sth->execute();                                                    \
my $results = $sth->fetchall_arrayref;                              \

[ map { $_->[0] } @${results} ]

HERE documents expressions

Is alternative to make your multiline code more readable:

# What about to validate stdout
# With sqlite database entries?

generator: <<CODE

use DBI;                                                            
my $dbh = DBI->connect("dbi:SQLite:dbname=t/data/test.db","","");   
my $sth = $dbh->prepare("SELECT name from users");                  
$sth->execute();                                                    
my $results = $sth->fetchall_arrayref;                              

[ map { $_->[0] } @${results} ]

CODE

Captures

Captures are pieces of data get captured when parser validate lines against a regular expressions:

Input text:

# my family ages list.
alex    38
julia   32
jan     2


# let's capture name and age chunks
regexp: /(\w+)\s+(\d+)/
code:                                   \
    for my $c (@{captures}){            \
        print "name:", $c->[0], "\n";   \
        print "age:", $c->[1], "\n";    \
    }

Data accessible via captures():

[
    ['alex',    38 ]
    ['julia',   32 ]
    ['jan',     2  ]
]

Then captured data usually good fit for validators extra checks.

Dsl code

validator: << CODE
my $total=0;                        
for my $c (@{captures()}) {         
    $total+=$c->[0];                
}                                   
[ ($total == 72 ), "total age of my family" ];

CODE

captures() function

captures() function returns an array reference holding all chunks captured during latest regular expression check.

Here some more examples.

Dsl code:

# check if stdout contains numbers,
# then calculate total amount
# and check if it is greater then 10

regexp: (\d+)

validator:  <<CODE
my $total=0;                        
for my $c (@{captures()}) {         
    $total+=$c->[0];                
}                                   
[ ( $total > 10 ) "total amount is greater than 10" ]

CODE


# check if stdout contains lines
# with date formatted as date: YYYY-MM-DD
# and then check if first date found is yesterday

regexp: date: (\d\d\d\d)-(\d\d)-(\d\d)

validator:  <<CODE
use DateTime;                       
my $c = captures()->[0];            
my $dt = DateTime->new( year => $c->[0], month => $c->[1], day => $c->[2]  ); 
my $yesterday = DateTime->now->subtract( days =>  1 );                        

[ ( DateTime->compare($dt, $yesterday) == 0 ),"first day found is - $dt and this is a yesterday" ];

CODE

capture() function

capture() function returns a first element of captures array.

it is useful when you need data related only first successfully matched line.

Dsl code:

# check if  text contains numbers
# a first number should be greater then ten

regexp: (\d+)
validator: [ ( capture()->[0] >  10 ), " first number is greater than 10 " ];

Search context modificators

Search context modificators are special check expressions which not only validate text but modify search context.

By default search context is equal to original input text stream.

That means parser executes validation use all the lines when performing checks

However there are two search context modificators to change this behavior:

  • within expressions

  • range expressions

Within expressions

Within expression acts like regular expression - checks text against given patterns

Text input:

These are my colors

color: red
color: green
color: blue
color: brown
color: back

That is it!

Dsl code:

# I need one of 3 colors:

within: color: (red|green|blue)

Then if checks given by within statement succeed next checks will be executed in a context of succeeded lines:

# but I really need a green one
green

The code above does follows:

  • try to validate input text against regular expression "color: (red|green|blue)"

  • if validation is successful new search context is set to all matching lines

These are:

color: red
color: green
color: blue

  • thus next plain string checks expression will be executed against new search context

Results:

+--------+------------------------------------------------+
| status | message                                        |
+--------+------------------------------------------------+
| OK     | matches /color: (red|green|blue)/              |
| OK     | /color: (red|green|blue)/ matches green        |
+--------+------------------------------------------------+

Here more examples:

# try to find a date string in following format
within: date: \d\d\d\d-\d\d-\d\d

# we only need a dates in 2000 year
2000-

Within expressions could be sequential, which effectively means using `&&' logical operators for within expressions:

# try to find a date string in following format
within: date: \d\d\d\d-\d\d-\d\d

# and try to find year of 2000 in a date string
within: 2000-\d\d-\d\d

# and try to find month 04 in a date string
within: \d\d\d\d-04-\d\d

Speaking in human language chained within expressions acts like specifications.

When you may start with some generic assumptions and then make your requirements more specific. A failure on any step of chain results in immediate break.

Range expressions

Range expressions also act like search context modificators - they change search area to one included between lines matching right and left regular expression of between statement.

It is very similar to what Perl range operator does when extracting pieces of lines inside stream:

while (<STDOUT>){
    if /foo/ ... /bar/
}

Outthentic analogy for this is range expression:

between: foo bar

Between statement takes 2 arguments - left and right regular expression to setup search area boundaries.

A search context will be all the lines included between line matching left expression and line matching right expression.

A matching (boundary) lines are not included in range.

These are few examples:

Parsing html output

Input text:

<table cols=10 rows=10>
    <tr>
        <td>one</td>
    </tr>
    <tr>
        <td>two</td>
    </tr>
    <tr>
        <td>the</td>
    </tr>
</table>

Dsl code:

# between expression:
between: <table.*> <\/table>
regexp: <td>(\S+)<\/td>

# or even so
between: <tr.*> <\/tr>
regexp: <td>(\S+)<\/td>

Multiple range expressions

Multiple range expressions could not be nested, every new between statement discards old search context and setup new one:

Input text:

foo

    1
    2
    3

    FOO
        100
    BAR

bar

FOO

    10
    20
    30

BAR

Dsl code:

between: foo bar

code: print "# foo/bar start"

# here will be everything
# between foo and bar lines

regexp: \d+

code: <<CODE                           
for my $i (@{captures()}) {     
    print "# ", $i->[0], "\n"   
}                               
print "# foo/bar end"

CODE

between: FOO BAR

code: print "# FOO/BAR start"

# here will be everything
# between FOO and BAR lines
# NOT necessarily inside foo bar block

regexp: \d+

code:  <<CODE
for my $i (@{captures()}) {     
    print "#", $i->[0], "\n";   
}                               
print "# FOO/BAR end"

CODE

Output:

    # foo/bar start
    # 1
    # 2
    # 3
    # 100
    # foo/bar end

    # FOO/BAR start
    # 100
    # 10
    # 20
    # 30
    # FOO/BAR end

Restoring search context

And finally to restore search context use `reset_context:' statement.

Input text:

hello
foo
    hello
    hello
bar

Dsl code:

between foo bar

# all check expressions here
# will be applied to the chunks
# between /foo/ ... /bar/

hello       # should match 2 times

# if you want to get back to an original search context
# just say reset_context:

reset_context:
hello       # should match three times

Range expressions caveats

Range expressions can't verify continuous lists.

That means range expression only verifies that there are some set of lines inside some range. It is not necessary should be continuous.

Example.

Input text:

foo
    1
    a
    2
    b
    3
    c
bar

Dsl code:

between: foo bar
    1
    code: print capture()->[0], "\n"
    2
    code: print capture()->[0], "\n"
    3
    code: print capture()->[0], "\n"

Output:

1 
2 
3

If you need check continuous sequences checks use text blocks.

Experimental features

Below is highly experimental features purely tested. You may use it on your own risk! ;)

Streams

Streams are alternative for captures. Consider following example.

Input text:

foo
    a
    b
    c
bar

foo
    1
    2
    3
bar

foo
    0
    00
    000
bar

Dsl code:

begin:

    foo

        regexp: (\S+)
        code: print '#', ( join ' ', map {$_->[0]} @{captures()} ), "\n"

        regexp: (\S+)
        code: print '#', ( join ' ', map {$_->[0]} @{captures()} ), "\n"

        regexp: (\S+)
        code: print '#', ( join ' ', map {$_->[0]} @{captures()} ), "\n"


    bar

end:

Output:

# a 1 0
# b 2 00
# c 3 000

Notice something interesting? Output direction has been inverted.

The reason for this is outthentic check expression works in "line by line scanning" mode when text input gets verified line by line against given check expression.

Once all lines are matched they get dropped into one heap without preserving original "group context".

What if we would like to print all matching lines grouped by text blocks they belong to?

As it's more convenient way ...

This is where streams feature comes to rescue.

Streams - are all the data successfully matched for given group context.

Streams are applicable for text blocks and range expressions.

Let's rewrite last example.

Dsl code:

begin:

    foo
        regexp: \S+
        regexp: \S+
        regexp: \S+
    bar

    code:  <<CODE
        for my $s (@{stream()}) {           
            print "# ";                     
            for my $i (@{$s}){              
                print $i;                   
            }                               
            print "\n";                     
        }

CODE

end:

Stream function returns an arrays of streams. Every stream holds all the matched lines for given logical block.

Streams preserve group context. Number of streams relates to the number of successfully matched groups.

Streams data presentation is much closer to what was originally given in text input:

Output:

# foo a b  c    bar
# foo 1 2  3    bar
# foo 0 00 000  bar

Stream could be specially useful when combined with range expressions of various ranges lengths.

For example.

Input text:

foo
    2
    4
    6
    8
bar

foo
    1
    3
bar

foo
    0
    0
    0
bar

Dsl code:

between: foo bar

regexp: \d+

code:  <<CODE
    for my $s (@{stream()}) {           
        print "# ";                     
        for my $i (@{$s}){              
            print $i;                   
        }                               
        print "\n";                     
    }

CODE

Output:

# 2 4 6 8
# 1 3
# 0 0 0

Inline code from other languages

WARNING!!! Don't use these features in production unless this message is removed.

One may use various languages in code and generators expressions. Here are examples.

bash

generator:  <<HERE

!/bin/bash
echo OK

HERE

code: <<HERE
mkdir -p /tmp/foo   
HERE

perl6

generator: <<PERL6

!/usr/bin/perl6

say 'OK';

PERL6

ruby

generator:  <<CODE
!/usr/bin/ruby

puts 'OK'

CODE

generator:  <<<CODE
!ruby

puts 'OK'

CODE

Author

Aleksei Melezhik

Home page

https://github.com/melezhik/outthentic-dsl

COPYRIGHT

Copyright 2015 Alexey Melezhik.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

See also

Alternative outthentic dsl introduction could be found here - intro.md

Thanks

  • to God as - For the LORD giveth wisdom: out of his mouth cometh knowledge and understanding. (Proverbs 2:6)