Reading, writing and handling files/directories why should a web developer care?
Tags: webdev, productivity, algorithms, programming
Published: 2022-12-23 18:57:25

I teach programming and sometimes while going through a class and its properties/methods a student will ask why they are learning a certain method and what can it be used for in the real world. With the exception of shell scripting and maybe python programmers Many programmers, especially self-thought programmers ignore certain things like how to read, write and handle files/directories in their chosen language.

Regardless of your chosen language here are some things you can do when you learn how to read, write and handle files/directories

1. Multi-themed applications 
2. Document generators
3. Website builders
4. Self-installing/updating apps
5. File-based data storage

## Multi-themed applications 
File and directory reading and writing functions can be useful in creating a multi-themed application, which is an application that allows the user to switch between multiple visual themes or styles.

1. To create this, you could follow these steps:
2. Determine the structure and content of the application, including the different visual themes or styles that will be available.
3. Create separate directories or files for each theme or style, and include the necessary CSS, image, and other files for each theme.
4. Write a program that uses the file and directory reading and writing functions to read in the appropriate theme or style files based on the user's selection. The program could also allow the user to create and save custom themes or styles.
5. Test the multi-themed application 

It's worth noting this process can be complex and requires careful planning and testing to ensure that the themes or styles are applied correctly and consistently throughout the application. Also, the specific steps and approach you take will depend on your specific needs and requirements. 

## Document generators
A document generator is a program that generates documents automatically, either by creating new documents from scratch or by modifying existing documents.
To create a document generator you could follow these steps:

1. Determine the type of documents you want to generate and the information that needs to be included in the documents.
2. Create a template for the documents, using placeholders for the information that will be filled in by the generator.
3. Iterate through the template and replace placeholders with the actual information, and generate the final documents.

This can be especially useful for generating large numbers of documents.

## Website builders
A website builder is a program that generates a website automatically.
To create a website you could follow these steps:

1. Determine the structure and content of the website that you want to generate. This could include the layout of the pages, the types of content that will be included (such as text, images, and videos), and the navigation structure of the site.
2. Create templates for the different types of pages/components and content that will be included on the website. These templates could include placeholders for the actual information that will be filled in by the builder.
3. Read in the templates and map placeholder to actual information and then generate the final website. The program could also create the necessary directories and files for the website, such as the HTML files for the pages, the CSS files for the styles, and the image and video files.

```
<?php

// Read in the template file
$template = file_get_contents('template.html');

// Read in the variable data from a CSV file
$data = array_map('str_getcsv', file('data.csv'));

// Replace the placeholders in the template with the actual data
$page = str_replace('[TITLE]', $data[0][0], $template);
$page = str_replace('[HEADING]', $data[0][1], $page);
$page = str_replace('[CONTENT]', $data[0][2], $page);

// Write the generated page to a file
$filename = 'index.html';
file_put_contents($filename, $page);
```


You could make the example above mor interactive by receiving actual information from the user through form elements and visually display the result as the fill out the forms

## Self-installing/updating apps
a self-installing or self-updating website, which is a website that can install or update itself automatically without requiring manual intervention.
To create a self-installing or self-updating website you could follow these steps:

1. Determine the structure and content of the website, including any updates or changes that will be made to the site.
2. Write the program by using the file and directory reading and writing functions to track the current version in the case of an update then download the necessary files for the website from a remote server and install them on the local server. 
3. It's worth noting that creating a self-installing or self-updating website can be complex and requires careful planning and testing to ensure that the process goes smoothly. For example, you will need to consider issues such as security, compatibility, and rollback in case of errors or incompatibility of system requirements.

## File-based data storage
To build a custom data storage system using file reading and writing functions in any programming language, you will need to perform the following steps:

1. Open a file in the appropriate mode (e.g. write mode to store data, read mode to retrieve data).
2. Write the data to the file using the appropriate method (e.g. write() in Python, fwrite() in C).
3. Close the file when you are finished writing to it.
4. Open the file again in the appropriate mode (e.g. read mode to retrieve data).
5. Read the data from the file using the appropriate method (e.g. read() in Python, fread() in C).
6. Close the file when you are finished reading from it.
7. Here is an example of how this might look in Python:

```
# Open a file in write mode
with open('data.txt', 'w') as f:
  # Write some data to the file
  f.write('This is some data that we are storing in the file.\n')
  f.write('We can store any type of data, such as numbers: 1, 2, 3\n')
  f.write('Or even lists: [1, 2, 3]\n')

# Open the file in read mode
with open('data.txt', 'r') as f:
  # Read the contents of the file
  contents = f.read()
  print(contents)
```

Note: The choice of data structures and algorithms can have a significant impact on the performance, efficiency, and scalability of the storage system; data structure and a sorting algorithm can allow for fast insertion and retrieval of data,