Add the function to create a motor from the API of thrustcurve and the test

Author: Marchma0

rocketpy/motors/motor.py

@@ -1,11 +1,14 @@
+import base64
 import re
+import tempfile
 import warnings
 import xml.etree.ElementTree as ET
 from abc import ABC, abstractmethod
 from functools import cached_property
 from os import path
 
 import numpy as np
+import requests
 
 from ..mathutils.function import Function, funcify_method
 from ..plots.motor_plots import _MotorPlots
@@ -1914,6 +1917,62 @@ def load_from_rse_file(
             coordinate_system_orientation=coordinate_system_orientation,
         )
 
+    @staticmethod
+    def load_from_thrustcurve_api(name: str, **kwargs):
+        """
+        Creates a Motor instance by downloading a .eng file from the ThrustCurve API
+        based on the given motor name.
+
+        Parameters
+        ----------
+        name : str
+            The motor name according to the API (e.g., "Cesaroni_M1670").
+        **kwargs :
+            Additional arguments passed to the Motor constructor, such as dry_mass, nozzle_radius, etc.
+
+        Returns
+        -------
+        instance : cls
+            A new Motor instance initialized using the downloaded .eng file.
+        """
+
+        base_url = "https://www.thrustcurve.org/api/v1"
+
+        # Step 1. Search motor
+        response = requests.get(f"{base_url}/search.json", params={"commonName": name})
+        response.raise_for_status()
+        data = response.json()
+
+        if not data.get("results"):
+            print("No motor found.")
+            return None
+
+        motor = data["results"][0]
+        motor_id = motor["motorId"]
+        designation = motor["designation"].replace("/", "-")
+        print(f"Motor found: {designation} ({motor['manufacturer']})")
+
+        # Step 2. Download the .eng file
+        dl_response = requests.get(
+            f"{base_url}/download.json",
+            params={"motorIds": motor_id, "format": "RASP", "data": "file"},
+        )
+        dl_response.raise_for_status()
+        data = dl_response.json()
+
+        data_base64 = data["results"][0]["data"]
+        data_bytes = base64.b64decode(data_base64)
+
+        # Step 3. Create the motor from the .eng file
+
+        with tempfile.NamedTemporaryFile(suffix=".eng", delete=True) as tmp_file:
+            tmp_file.write(data_bytes)
+            tmp_file.flush()
+
+            motor = GenericMotor.load_from_eng_file(tmp_file.name, **kwargs)
+
+        return motor
+
     def all_info(self):
         """Prints out all data and graphs available about the Motor."""
         # Print motor details

tests/unit/motors/test_genericmotor.py

@@ -211,3 +211,50 @@ def test_load_from_rse_file(generic_motor):
     assert thrust_curve[0][1] == 0.0  # First thrust point
     assert thrust_curve[-1][0] == 2.2  # Last point of time
     assert thrust_curve[-1][1] == 0.0  # Last thrust point
+
+
+def test_load_from_thrustcurve_api(generic_motor):
+    """Tests the GenericMotor.load_from_thrustcurve_api method.
+
+    Parameters
+    ----------
+    generic_motor : rocketpy.GenericMotor
+        The GenericMotor object to be used in the tests.
+    """
+    # using cesaroni data as example
+    burn_time = (0, 3.9)
+    dry_mass = 5.231 - 3.101  # 2.130 kg
+    propellant_initial_mass = 3.101
+    chamber_radius = 75 / 1000
+    chamber_height = 757 / 1000
+    nozzle_radius = chamber_radius * 0.85  # 85% of chamber radius
+
+    # Parameters from manual testing using the SolidMotor class as a reference
+    average_thrust = 1545.218
+    total_impulse = 6026.350
+    max_thrust = 2200.0
+    exhaust_velocity = 1943.357
+
+    # creating motor from .eng file
+    generic_motor = generic_motor.load_from_thrustcurve_api("M1670")
+
+    # testing relevant parameters
+    assert generic_motor.burn_time == burn_time
+    assert generic_motor.dry_mass == dry_mass
+    assert generic_motor.propellant_initial_mass == propellant_initial_mass
+    assert generic_motor.chamber_radius == chamber_radius
+    assert generic_motor.chamber_height == chamber_height
+    assert generic_motor.chamber_position == 0
+    assert generic_motor.average_thrust == pytest.approx(average_thrust)
+    assert generic_motor.total_impulse == pytest.approx(total_impulse)
+    assert generic_motor.exhaust_velocity.average(*burn_time) == pytest.approx(
+        exhaust_velocity
+    )
+    assert generic_motor.max_thrust == pytest.approx(max_thrust)
+    assert generic_motor.nozzle_radius == pytest.approx(nozzle_radius)
+
+    # testing thrust curve
+    _, _, points = Motor.import_eng("data/motors/cesaroni/Cesaroni_M1670.eng")
+    assert generic_motor.thrust.y_array == pytest.approx(
+        Function(points, "Time (s)", "Thrust (N)", "linear", "zero").y_array
+    )