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Overview

The client application (backend/client.py) demonstrates how to connect to the remote Conversor service and invoke its methods using ZeroC ICE.

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Client Initialization

1

Import the ICE library and generated stubs

import Ice
import Conversor  # Generated module from slice2py
2

Initialize the ICE communicator

The communicator is the main entry point for ICE functionality.
with Ice.initialize(sys.argv) as communicator:
    # Client code here
Using a context manager ensures proper cleanup when the client exits.
3

Create a proxy to the remote object

base = communicator.stringToProxy(
    "ConversorUnidades:default -h localhost -p 10000"
)
The proxy string format is:
ObjectName:protocol -h hostname -p port
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ConversorUnidades
string
The identity name registered on the server
​
default
string
Protocol type (TCP in this case)
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localhost
string
Server hostname or IP address
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10000
number
Server port number
4

Cast the proxy to the specific interface type

conversor = Conversor.ConversorUnidadesPrx.checkedCast(base)

if not conversor:
    raise RuntimeError("No se pudo obtener el proxy del servidor.")
checkedCast verifies at runtime that the remote object implements the expected interface. Always check if the result is None.

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Making Remote Calls

Once you have the proxy, calling remote methods looks like local function calls:

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Temperature Conversion

# 100 Celsius to Fahrenheit
result = conversor.convertirTemperatura(100, "celsius", "fahrenheit")
print(f"100 celsius -> fahrenheit: {result:.4f}")  # 212.0000

# 0 Celsius to Kelvin
result = conversor.convertirTemperatura(0, "celsius", "kelvin")
print(f"0 celsius -> kelvin: {result:.4f}")  # 273.1500

# 98.6 Fahrenheit to Celsius
result = conversor.convertirTemperatura(98.6, "fahrenheit", "celsius")
print(f"98.6 fahrenheit -> celsius: {result:.4f}")  # 37.0000

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Length Conversion

# 1 Mile to Kilometers
result = conversor.convertirLongitud(1, "mi", "km")
print(f"1 mi -> km: {result:.4f}")  # 1.6093

# 100 Feet to Meters
result = conversor.convertirLongitud(100, "ft", "m")
print(f"100 ft -> m: {result:.4f}")  # 30.4800

# 5 Kilometers to Meters
result = conversor.convertirLongitud(5, "km", "m")
print(f"5 km -> m: {result:.4f}")  # 5000.0000

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Weight Conversion

# 70 Kilograms to Pounds
result = conversor.convertirPeso(70, "kg", "lb")
print(f"70 kg -> lb: {result:.4f}")  # 154.3235

# 1 Pound to Grams
result = conversor.convertirPeso(1, "lb", "g")
print(f"1 lb -> g: {result:.4f}")  # 453.5920

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Velocity Conversion

# 120 km/h to mph
result = conversor.convertirVelocidad(120, "kmh", "mph")
print(f"120 kmh -> mph: {result:.4f}")  # 74.5645

# 60 mph to m/s
result = conversor.convertirVelocidad(60, "mph", "ms")
print(f"60 mph -> ms: {result:.4f}")  # 26.8224

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Query Available Units

for categoria in ["temperatura", "longitud", "peso", "velocidad"]:
    unidades = conversor.unidadesDisponibles(categoria)
    print(f"{categoria}: {unidades}")

# Output:
# temperatura: celsius, fahrenheit, kelvin
# longitud: m, km, mi, ft
# peso: kg, lb, g
# velocidad: kmh, mph, ms

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Exception Handling

ICE exceptions are serialized and propagated from server to client: 
try:
    result = conversor.convertirTemperatura(100, "invalid", "celsius")
except Conversor.UnidadInvalidaException as e:
    print(f"Error de conversion: {e.mensaje}")
    # Error de conversion: Unidad origen 'invalid' no valida para temperatura. 
    # Validas: celsius, fahrenheit, kelvin
The exception contains a descriptive mensaje field that explains exactly what went wrong, including which units are valid.

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Complete Client Example

Here’s the full client code from backend/client.py: 
import sys
import os
import Ice

CURRENT_DIR = os.path.dirname(os.path.abspath(__file__))
PROJECT_ROOT = os.path.dirname(CURRENT_DIR)
if PROJECT_ROOT not in sys.path:
    sys.path.insert(0, PROJECT_ROOT)

import Conversor

def main():
    with Ice.initialize(sys.argv) as communicator:
        base = communicator.stringToProxy(
            "ConversorUnidades:default -h localhost -p 10000"
        )
        
        conversor = Conversor.ConversorUnidadesPrx.checkedCast(base)
        
        if not conversor:
            raise RuntimeError("No se pudo obtener el proxy del servidor.")
        
        try:
            print("=== TEMPERATURA ===")
            r = conversor.convertirTemperatura(100, "celsius", "fahrenheit")
            print(f"100 celsius -> fahrenheit: {r:.4f}")
            
            r = conversor.convertirTemperatura(0, "celsius", "kelvin")
            print(f"0 celsius -> kelvin: {r:.4f}")
            
            r = conversor.convertirTemperatura(98.6, "fahrenheit", "celsius")
            print(f"98.6 fahrenheit -> celsius: {r:.4f}")
            
            print("\n=== LONGITUD ===")
            r = conversor.convertirLongitud(1, "mi", "km")
            print(f"1 mi -> km: {r:.4f}")
            
            r = conversor.convertirLongitud(100, "ft", "m")
            print(f"100 ft -> m: {r:.4f}")
            
            r = conversor.convertirLongitud(5, "km", "m")
            print(f"5 km -> m: {r:.4f}")
            
            print("\n=== PESO ===")
            r = conversor.convertirPeso(70, "kg", "lb")
            print(f"70 kg -> lb: {r:.4f}")
            
            r = conversor.convertirPeso(1, "lb", "g")
            print(f"1 lb -> g: {r:.4f}")
            
            print("\n=== VELOCIDAD ===")
            r = conversor.convertirVelocidad(120, "kmh", "mph")
            print(f"120 kmh -> mph: {r:.4f}")
            
            r = conversor.convertirVelocidad(60, "mph", "ms")
            print(f"60 mph -> ms: {r:.4f}")
            
            print("\n=== UNIDADES DISPONIBLES ===")
            for cat in ["temperatura", "longitud", "peso", "velocidad"]:
                print(f"{cat}: {conversor.unidadesDisponibles(cat)}")
        
        except Conversor.UnidadInvalidaException as e:
            print(f"Error de conversion: {e.mensaje}")

if __name__ == "__main__":
    main()

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Running the Client

1

Ensure the server is running

The server must be started first on port 10000.
python backend/server.py
2

Run the client

python backend/client.py
3

View the output

The client will execute all conversion examples and display results.

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Key Concepts

Proxy

A local object that represents the remote server object. Method calls on the proxy are transparently converted to network requests.

Communicator

The ICE runtime that manages connections, threading, and protocol handling.

checkedCast

Runtime verification that the remote object implements the expected interface.

Exception Propagation

Server exceptions are serialized and re-thrown on the client side.

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Next Steps

Server Implementation

Learn how the server implements the conversion logic

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