Use Cases & Examples
Real-world examples of using datalogic-rs for common scenarios.
Feature Flags
Control feature availability based on user attributes.
Basic Feature Flag
#![allow(unused)]
fn main() {
use datalogic_rs::DataLogic;
use serde_json::json;
let engine = DataLogic::new();
// Feature available to premium users in US
let rule = json!({
"and": [
{ "==": [{ "var": "user.plan" }, "premium"] },
{ "==": [{ "var": "user.country" }, "US"] }
]
});
let compiled = engine.compile(&rule).unwrap();
let user_data = json!({
"user": {
"plan": "premium",
"country": "US"
}
});
let enabled = engine.evaluate_owned(&compiled, user_data).unwrap();
assert_eq!(enabled, json!(true));
}Percentage Rollout
#![allow(unused)]
fn main() {
// Enable for 20% of users (based on user ID hash)
let rule = json!({
"<": [
{ "%": [{ "var": "user.id" }, 100] },
20
]
});
}Beta Access
#![allow(unused)]
fn main() {
// Enable for beta testers OR employees OR users who signed up before a date
let rule = json!({
"or": [
{ "==": [{ "var": "user.role" }, "beta_tester"] },
{ "ends_with": [{ "var": "user.email" }, "@company.com"] },
{ "<": [{ "var": "user.signup_date" }, "2024-01-01"] }
]
});
}Dynamic Pricing
Calculate prices based on rules.
Discount by Quantity
#![allow(unused)]
fn main() {
let rule = json!({
"if": [
{ ">=": [{ "var": "quantity" }, 100] },
{ "*": [{ "var": "base_price" }, 0.8] }, // 20% off
{ "if": [
{ ">=": [{ "var": "quantity" }, 50] },
{ "*": [{ "var": "base_price" }, 0.9] }, // 10% off
{ "var": "base_price" }
]}
]
});
let data = json!({
"quantity": 75,
"base_price": 100
});
let price = engine.evaluate_owned(&compiled, data).unwrap();
// Result: 90 (10% discount)
}Tiered Pricing
#![allow(unused)]
fn main() {
let rule = json!({
"+": [
// First 10 units at $10
{ "*": [{ "min": [{ "var": "quantity" }, 10] }, 10] },
// Next 40 units at $8
{ "*": [
{ "max": [{ "-": [{ "min": [{ "var": "quantity" }, 50] }, 10] }, 0] },
8
]},
// Remaining units at $6
{ "*": [
{ "max": [{ "-": [{ "var": "quantity" }, 50] }, 0] },
6
]}
]
});
}Member Pricing
#![allow(unused)]
fn main() {
let rule = json!({
"if": [
{ "var": "user.is_member" },
{ "*": [
{ "var": "product.price" },
{ "-": [1, { "/": [{ "var": "user.member_discount" }, 100] }] }
]},
{ "var": "product.price" }
]
});
let data = json!({
"user": { "is_member": true, "member_discount": 15 },
"product": { "price": 200 }
});
// Result: 170 (15% member discount)
}Form Validation
Validate user input with complex rules.
Required Fields
#![allow(unused)]
fn main() {
let rule = json!({
"if": [
{ "missing": ["name", "email", "password"] },
{
"valid": false,
"errors": { "missing": ["name", "email", "password"] }
},
{ "valid": true }
]
});
}Field Constraints
#![allow(unused)]
fn main() {
let engine = DataLogic::with_preserve_structure();
let rule = json!({
"valid": { "and": [
// Email format
{ "in": ["@", { "var": "email" }] },
// Password length
{ ">=": [{ "length": { "var": "password" } }, 8] },
// Age range
{ "and": [
{ ">=": [{ "var": "age" }, 18] },
{ "<=": [{ "var": "age" }, 120] }
]}
]},
"errors": { "filter": [
[
{ "if": [
{ "!": { "in": ["@", { "var": "email" }] } },
"Invalid email format",
null
]},
{ "if": [
{ "<": [{ "length": { "var": "password" } }, 8] },
"Password must be at least 8 characters",
null
]},
{ "if": [
{ "or": [
{ "<": [{ "var": "age" }, 18] },
{ ">": [{ "var": "age" }, 120] }
]},
"Age must be between 18 and 120",
null
]}
],
{ "!==": [{ "var": "" }, null] }
]}
});
}Conditional Validation
#![allow(unused)]
fn main() {
// If business account, require company name
let rule = json!({
"if": [
{ "and": [
{ "==": [{ "var": "account_type" }, "business"] },
{ "missing": ["company_name"] }
]},
{ "error": "Company name required for business accounts" },
{ "valid": true }
]
});
}Access Control
Determine user permissions.
Role-Based Access
#![allow(unused)]
fn main() {
let rule = json!({
"or": [
{ "==": [{ "var": "user.role" }, "admin"] },
{ "and": [
{ "==": [{ "var": "user.role" }, "editor"] },
{ "==": [{ "var": "resource.owner_id" }, { "var": "user.id" }] }
]}
]
});
}Permission Checking
#![allow(unused)]
fn main() {
let rule = json!({
"in": [
{ "var": "required_permission" },
{ "var": "user.permissions" }
]
});
let data = json!({
"user": {
"permissions": ["read", "write", "delete"]
},
"required_permission": "write"
});
// Result: true
}Time-Based Access
#![allow(unused)]
fn main() {
let rule = json!({
"and": [
// Has permission
{ "in": ["access_data", { "var": "user.permissions" }] },
// Within allowed hours (9 AM - 6 PM)
{ "and": [
{ ">=": [{ "var": "current_hour" }, 9] },
{ "<": [{ "var": "current_hour" }, 18] }
]},
// On a weekday
{ "in": [{ "var": "current_day" }, [1, 2, 3, 4, 5]] }
]
});
}Fraud Detection
Score and flag potentially fraudulent transactions.
Risk Scoring
#![allow(unused)]
fn main() {
let rule = json!({
"+": [
// High amount
{ "if": [{ ">": [{ "var": "amount" }, 1000] }, 30, 0] },
// New account
{ "if": [{ "<": [{ "var": "account_age_days" }, 7] }, 25, 0] },
// Different country
{ "if": [
{ "!=": [{ "var": "billing_country" }, { "var": "shipping_country" }] },
20,
0
]},
// Multiple attempts
{ "if": [{ ">": [{ "var": "attempts_last_hour" }, 3] }, 25, 0] },
// Unusual time
{ "if": [
{ "or": [
{ "<": [{ "var": "hour" }, 6] },
{ ">": [{ "var": "hour" }, 23] }
]},
15,
0
]}
]
});
// Score > 50 = flag for review
let data = json!({
"amount": 1500,
"account_age_days": 3,
"billing_country": "US",
"shipping_country": "CA",
"attempts_last_hour": 1,
"hour": 14
});
// Result: 75 (high amount + new account + different country)
}Velocity Checks
#![allow(unused)]
fn main() {
let rule = json!({
"or": [
// Too many transactions in short time
{ ">": [{ "var": "transactions_last_hour" }, 10] },
// Too much total amount
{ ">": [{ "var": "total_amount_last_hour" }, 5000] },
// Same card used from multiple IPs
{ ">": [{ "var": "unique_ips_last_day" }, 3] }
]
});
}Data Transformation
Transform and reshape data.
API Response Mapping
#![allow(unused)]
fn main() {
let engine = DataLogic::with_preserve_structure();
let template = json!({
"users": {
"map": [
{ "var": "raw_users" },
{
"id": { "var": "user_id" },
"fullName": { "cat": [{ "var": "first_name" }, " ", { "var": "last_name" }] },
"email": { "lower": { "var": "email" } },
"isActive": { "==": [{ "var": "status" }, "active"] }
}
]
},
"total": { "length": { "var": "raw_users" } },
"activeCount": { "length": {
"filter": [
{ "var": "raw_users" },
{ "==": [{ "var": "status" }, "active"] }
]
}}
});
}Report Generation
#![allow(unused)]
fn main() {
let template = json!({
"report": {
"title": { "cat": ["Sales Report - ", { "var": "period" }] },
"generated": { "format_date": [{ "now": [] }, "%Y-%m-%d %H:%M"] },
"summary": {
"totalSales": { "reduce": [
{ "var": "transactions" },
{ "+": [{ "var": "accumulator" }, { "var": "current.amount" }] },
0
]},
"avgTransaction": { "/": [
{ "reduce": [
{ "var": "transactions" },
{ "+": [{ "var": "accumulator" }, { "var": "current.amount" }] },
0
]},
{ "length": { "var": "transactions" } }
]},
"topCategory": { "var": "top_category" }
}
}
});
}Notification Rules
Determine when and how to send notifications.
Alert Conditions
#![allow(unused)]
fn main() {
let rule = json!({
"if": [
// Critical: immediate
{ ">": [{ "var": "error_rate" }, 10] },
{ "channel": "pager", "priority": "critical" },
// Warning: Slack
{ "if": [
{ ">": [{ "var": "error_rate" }, 5] },
{ "channel": "slack", "priority": "warning" },
// Info: email digest
{ "if": [
{ ">": [{ "var": "error_rate" }, 1] },
{ "channel": "email", "priority": "info" },
null
]}
]}
]
});
}User Preferences
#![allow(unused)]
fn main() {
let rule = json!({
"and": [
// User has enabled notifications
{ "var": "user.notifications_enabled" },
// Notification type is in user's preferences
{ "in": [
{ "var": "notification.type" },
{ "var": "user.enabled_types" }
]},
// Within user's quiet hours
{ "!": { "and": [
{ ">=": [{ "var": "current_hour" }, { "var": "user.quiet_start" }] },
{ "<": [{ "var": "current_hour" }, { "var": "user.quiet_end" }] }
]}}
]
});
}