feature to download the spectrum file (.spec)

server/main.py

@@ -1,9 +1,11 @@
+import radis
+import datetime
 from typing import List, Optional
-from fastapi import FastAPI
+from fastapi import BackgroundTasks, FastAPI
 from pydantic import BaseModel
-import radis
 from fastapi.middleware.cors import CORSMiddleware
 from pydantic.typing import Literal
+from fastapi.responses import FileResponse
 # for high resolution
 radis.config["GRIDPOINTS_PER_LINEWIDTH_WARN_THRESHOLD"] = 7
 app = FastAPI()
@@ -31,50 +33,62 @@ class Payload(BaseModel):
     tvib: Optional[float] = None
     trot: Optional[float] = None
     path_length: float
-    simulate_slit: Optional[int] = None
+    simulate_slit: Optional[int]
     mode: Literal["absorbance", "transmittance_noslit", "radiance_noslit", "transmittance", "radiance"]
     database: Literal["hitran", "geisa"]
     use_simulate_slit: bool = False
 
 
+def calculate_spectrum(payload):
+    global spectrum
+    spectrum = radis.calc_spectrum(
+        payload.min_wavenumber_range,
+        payload.max_wavenumber_range,
+        molecule=[species.molecule for species in payload.species],
+        mole_fraction={
+            species.molecule: species.mole_fraction for species in payload.species
+        },
+        # TODO: Hard-coding "1,2,3" as the isotopologue for the time-being
+        isotope={species.molecule: "1,2,3" for species in payload.species},
+        pressure=payload.pressure,
+        Tgas=payload.tgas,
+        Tvib=payload.tvib,
+        Trot=payload.trot,
+        path_length=payload.path_length,
+        export_lines=False,
+        wstep="auto",
+        databank=payload.database,
+        use_cached=True,
+    )
+def download_spec_file():
+    file_name_notation = datetime.datetime.now()
+    global file_name
+    file_name = f'radis{file_name_notation}.spec'
+    spectrum.store(file_name, compress=True, if_exists_then='replace')
+    return "spectrum file is created successfully"
+def return_spec_file():
+    return FileResponse(file_name, media_type='application/octet-stream', filename=f'{file_name}.txt')
+
+
 @app.post("/calculate-spectrum")
-async def calculate_spectrum(payload: Payload):
+async def calculate_spectrum(payload: Payload, background_taks: BackgroundTasks):
     print(payload)
-
     try:
-        spectrum = radis.calc_spectrum(
-            payload.min_wavenumber_range,
-            payload.max_wavenumber_range,
-            molecule=[species.molecule for species in payload.species],
-            mole_fraction={
-                species.molecule: species.mole_fraction for species in payload.species
-            },
-            # TODO: Hard-coding "1,2,3" as the isotopologue for the time-being
-            isotope={species.molecule: "1,2,3" for species in payload.species},
-            pressure=payload.pressure,
-            Tgas=payload.tgas,
-            Tvib=payload.tvib,
-            Trot=payload.trot,
-            path_length=payload.path_length,
-            export_lines=False,
-            wstep="auto",
-            databank=payload.database,
-            use_cached=True,
-        )
+        calculate_spectrum(payload)
         if payload.use_simulate_slit is True:
             spectrum.apply_slit(payload.simulate_slit, "nm")
-
+        # downloading the molecule as a background task so that the retrieving
+        # x and y values are are not effected
+        background_taks.add_task(download_spec())
     except radis.misc.warning.EmptyDatabaseError:
         return {"error": "No line in the specified wavenumber range"}
     except Exception as exc:
         print("Error", exc)
         return {"error": str(exc)}
     else:
-
         wunit = spectrum.get_waveunit()
         iunit = "default"
         x, y = spectrum.get(payload.mode, wunit=wunit, Iunit=iunit)
-
         # Reduce payload size
         threshold = 5e7
         if len(spectrum) * 8 * 2 > threshold:
@@ -86,11 +100,23 @@ async def calculate_spectrum(payload: Payload):
             #     from the x min, max and step --> less data transfer. TODO )
             resample = int(len(spectrum) * 8 * 2 // threshold)
             x, y = x[::resample], y[::resample]
+            return {
+                "data": {
+                    "x": list(x),
+                    "y": list(y),
+                    "units": spectrum.units[payload.mode],
+                },
+            }
 
-        return {
-            "data": {
-                "x": list(x),
-                "y": list(y),
-                "units": spectrum.units[payload.mode],
-            },
-        }
+
+@app.get("/download")
+async def download():
+    try:
+        return_spec_file()
+    except radis.misc.warning.EmptyDatabaseError:
+        return {"error": "No line in the specified wavenumber range"}
+    except Exception as exc:
+        print("Error", exc)
+        return {"error": str(exc)}
+    else:
+        return "file returned successfully"