example_4.cpp

[example_cpp]

[example_cpp] This example shows how to connect together many transformers. In this example we have two transformer. The first filter out mails by keyword "Hello". The second one cancels all process if reach the limit of 10 mails.

 
#include <iostream>
#include <memory>
 
#include "parser.h"
#include "importer.h"
#include "exporter.h"
#include "transformer.h"
#include "parsing_chain.h"
 
int main(int argc, char* argv[])
{
  doctotext::Importer(argv[1]) | doctotext::TransformerFunc([](doctotext::Info &info) // Create an importer from file name and connect it to transformer
                                           {
                                             if (info.tag_name == doctotext::StandardTag::TAG_MAIL) // if current node is mail
                                             {
                                               auto subject = info.getAttributeValue<std::string>("subject"); // get the subject attribute
                                               if (subject) // if subject attribute exists
                                               {
                                                 if (subject->find("Hello") != std::string::npos) // if subject contains "Hello"
                                                 {
                                                   info.skip = true; // skip the current node
                                                 }
                                               }
                                             }
                                           })
                    | doctotext::TransformerFunc([counter = 0, max_mails = 1](doctotext::Info &info) mutable // Create a transformer and connect it to previous transformer
                                           {
                                             if (info.tag_name == doctotext::StandardTag::TAG_MAIL) // if current node is mail
                                             {
                                               if (++counter > max_mails) // if counter is greater than max_mails
                                               {
                                                info.cancel = true; // cancel the parsing process
                                               }
                                             }
                                           })
                    | doctotext::PlainTextExporter() // sets exporter to plain text
                    | std::cout; // sets output stream
 return 0;
}