Helper Utilities

This module provides reusable utility functions used across the application.

The helper functions cover:

• Datetime formatting
• String normalization
• Empty value validation
• Email validation
• Name validation
• Price validation
• Sequence generation
• Module prefix formatting

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File Structure

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Module Dependencies

use chrono::{DateTime, Local};
use regex::Regex;
use crate::utils::Responses;
use axum::{http::StatusCode, response::{AppendHeaders, IntoResponse, Response}, Json};
use serde::Serializer;
use serde_json::json;

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Helper Function Overview

Function	Purpose
time_now_modif	Get current local datetime
format_datetime	Serialize datetime into formatted string
convert_to_normalize_lower	Normalize string to lowercase
is_empty	Check empty string
not_empty	Check non-empty string
is_valid_name	Validate name format
is_valid_email	Validate email format
is_valid_price	Validate numeric price
sequence_number	Generate padded sequence number
prefix_module	Generate prefixed document code
splits_prefix_module	Validate module prefix

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Utility Architecture

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Current Datetime Helper

Source Code

//format : 2026-05-07 14:30:00
#[allow(dead_code)]
pub fn time_now_modif() -> DateTime<Local>  {
    Local::now()
}

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Explanation

Returns the current local datetime using Chrono.

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Return Type

DateTime<Local>

Represents timezone-aware local datetime.

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Datetime Formatter

Source Code

pub fn format_datetime<S>(
    date: &Option<DateTime<Local>>,
    serializer: S,
) -> Result<S::Ok, S::Error>
where
    S: Serializer,
{
    match date {
        Some(dt) => serializer.serialize_str(
            &dt.format("%Y-%m-%d %H:%M:%S").to_string()
        ),
        None => serializer.serialize_none(),
    }
}

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Datetime Serialization Flow

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Datetime Format

2026-05-07 14:30:00

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String Normalization

Source Code

// trim + lower
#[allow(dead_code)]
pub fn convert_to_normalize_lower(value:&str)->String{
    value.trim().to_lowercase()
}

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Explanation

Performs:

• Whitespace trimming
• Lowercase conversion

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Example

Input	Output
" ADMIN "	"admin"

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Empty String Validation

is_empty

pub fn is_empty(value:&str)->bool{
    value.trim().is_empty()
}

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Explanation

Checks whether a string is empty after trimming whitespace.

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Example

Input	Result
" "	true
"hello"	false

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Non-Empty Validation

Source Code

/// Check not empty string
#[allow(dead_code)]
pub fn not_empty(value: &str) -> bool {
    !value.trim().is_empty()
}

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Explanation

Returns the inverse result of is_empty.

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Name Validation

Source Code

/// Valid name:
/// a-z A-Z 0-9 . space
#[allow(dead_code)]
pub fn is_valid_name(name: &str) -> bool {
    let regex = Regex::new(r"^[a-zA-Z0-9.\s]+$").unwrap();
    regex.is_match(name)
}

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Allowed Characters

Character Type	Allowed
Uppercase letters	Yes
Lowercase letters	Yes
Numbers	Yes
Dot (.)	Yes
Space	Yes

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Regex Pattern

^[a-zA-Z0-9.\s]+$

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Validation Examples

Input	Result
"John Doe"	true
"User.01"	true
"Admin@Root"	false

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Email Validation

Source Code

/// Validate email
pub fn is_valid_email(email: &str) -> bool {
    let regex =
        Regex::new(r"^[a-zA-Z0-9._%+\-]+@[a-zA-Z0-9.\-]+\.[a-zA-Z]{2,}$").unwrap();

    regex.is_match(email)
}

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Email Validation Flow

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Supported Email Format

Examples:

user@example.com
admin.system@test.org

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Price Validation

Source Code

/// Validate price
/// only number + dot + space
#[allow(dead_code)]
pub fn is_valid_price(price: &str) -> bool {
    let regex = Regex::new(r"^[0-9.\s]+$").unwrap();
    regex.is_match(price)
}

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Allowed Characters

Character	Allowed
Numbers	Yes
Dot (.)	Yes
Space	Yes

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Example

Input	Result
"1000"	true
"10.500"	true
"1000USD"	false

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Sequence Number Generator

Source Code

/// Example:
/// 1 => 000001
#[allow(dead_code)]
pub fn sequence_number(n: i64) -> String {
    format!("{:06}", n)
}

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Sequence Format

Pads numbers into 6-digit format.

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Examples

Input	Output
1	000001
25	000025
1000	001000

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Prefix Module Generator

Source Code

/// Example:
/// INV-2605000001
pub fn prefix_module(code: &str, seq: i64) -> String {
    let date = Local::now().format("%y%m").to_string();

    format!("{}-{}{}", code, date, sequence_number(seq))
}

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Prefix Format Structure

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Format Example

INV-2605000001

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Format Breakdown

Segment	Description
INV	Module code
2605	Year and month
000001	Sequence number

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Prefix Validation

Source Code

pub fn splits_prefix_module(code:&str, value:&str) ->bool{
    value.trim().to_lowercase().starts_with(&format!("{}-",code.trim().to_lowercase()))
}

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Explanation

Checks whether a value starts with a specific module prefix.

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Validation Example

Code	Value	Result
INV	INV-2605000001	true
TRX	INV-2605000001	false

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Validation Logic

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Utility Design Summary

Category	Responsibility
Datetime Utility	Current time and formatting
String Utility	Normalize and trim values
Validation Utility	Validate names, emails, prices
Sequence Utility	Generate formatted identifiers
Prefix Utility	Validate module codes

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Design Characteristics

Lightweight

Functions are reusable and independent.

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Stateless

No shared mutable state is used.

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Reusable

Can be reused across:

• Services
• Middleware
• Validation layers
• Response formatting
• Database modules

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Common Use Cases

Feature	Helper Function
Generate invoice number	prefix_module
Validate email input	is_valid_email
Normalize user input	convert_to_normalize_lower
Serialize datetime response	format_datetime
Validate empty form field	is_empty
Validate product price	is_valid_price