PyPNM FastAPI - PNM Capture cURL Examples

This guide shows how to invoke PyPNM PNM capture endpoints using curl. Each example sends a POST request with a JSON body that mirrors the common FastAPI request models.

Table Of Contents

Overview

Common Request Template

Downstream OFDM Capture Endpoints

• Downstream OFDM RxMER
• Downstream OFDM Channel Estimation
• Downstream OFDM FEC Summary
• Downstream OFDM Modulation Profile
• Downstream OFDM Constellation Display
• Downstream Spectrum Analysis

Upstream OFDMA Capture Endpoints

• Upstream OFDMA Pre-Equalization

Programming Notes

Overview

PNM capture endpoints in PyPNM are all POST operations that accept a JSON body based on a shared request model (for example, CommonRequest / PnmSingleCaptureRequest).

Representative routers and services:

• CmDsOfdmRxMerService
• CmDsOfdmChanEstimateCoef
• CmDsOfdmFecSummary
• CmDsOfdmModulationProfile
• CmSpectrumAnalysis
• CmUsOfdmaPreEq

The examples focus on how to structure the JSON and how to invoke the endpoints with curl. Response payloads are typically JSON containing PNM metadata and capture file information. Archive/plot outputs follow the same request shape but use a different analysis.output.type value.

For all examples below, generic addresses are used:

• Example CM MAC address: aa:bb:cc:dd:ee:ff
• Example CM IP address: 192.168.0.100
• Example TFTP server (IPv4): 192.168.0.200
• Example TFTP server (IPv6): ::1 (dummy placeholder)

Common Request Template

Most PNM capture endpoints accept a request with this common structure (simplified).

Key details for the current implementation:

• analysis.output.type uses lowercase strings ("json", "archive", etc.).
• analysis.plot is required for single-capture analysis routes; RxMER needs at least plot.ui.theme.
• pnm_parameters.tftp.ipv6 can safely use a dummy address ::1 if IPv6 is not otherwise used.

curl -X POST "http://127.0.0.1:8000/<endpoint>"   -H "Content-Type: application/json"   -d @- << 'JSON'
{
  "cable_modem": {
    "mac_address": "aa:bb:cc:dd:ee:ff",
    "ip_address": "192.168.0.100",
    "snmp": {
      "snmp_v2c": {
        "community": "private"
      }
    },
    "pnm_parameters": {
      "tftp": {
        "ipv4": "192.168.0.200",
        "ipv6": "::1",
        "dest_dir": ""
      },
      "capture": {
        "channel_ids": []
      }
    }
  },
  "analysis": {
    "output": {
      "type": "json"
    },
    "plot": {
      "ui": {
        "theme": "dark"
      }
    }
  }
}
JSON

You can reuse this block and only change the <endpoint> path for each PNM capture.

Downstream OFDM Capture Endpoints

Downstream OFDM RxMER

Endpoint:

• POST /docs/pnm/ds/ofdm/rxMer/getCapture

This is a validated RxMER pattern using the generic MAC/IP/TFTP and the required analysis.plot.ui.theme field:

curl -X POST "http://127.0.0.1:8000/docs/pnm/ds/ofdm/rxMer/getCapture"   -H "Content-Type: application/json"   -d @- << 'JSON'
{
  "cable_modem": {
    "mac_address": "aa:bb:cc:dd:ee:ff",
    "ip_address": "192.168.0.100",
    "snmp": {
      "snmp_v2c": {
        "community": "private"
      }
    },
    "pnm_parameters": {
      "tftp": {
        "ipv4": "192.168.0.200",
        "ipv6": "::1",
        "dest_dir": ""
      },
      "capture": {
        "channel_ids": []
      }
    }
  },
  "analysis": {
    "output": {
      "type": "json"
    },
    "plot": {
      "ui": {
        "theme": "dark"
      }
    }
  }
}
JSON

The response payload corresponds to the RxMER analysis model returned by your Analysis(AnalysisType.BASIC, msg_rsp) path, combined with RxMER measurement stats.

Downstream OFDM Channel Estimation

Endpoint:

• POST /docs/pnm/ds/ofdm/chanEstimate/getCapture

Channel estimation uses the same overall request shape. If the underlying route uses the same CommonAnalysisRequest, this template should validate:

curl -X POST "http://127.0.0.1:8000/docs/pnm/ds/ofdm/chanEstimate/getCapture"   -H "Content-Type: application/json"   -d @- << 'JSON'
{
  "cable_modem": {
    "mac_address": "aa:bb:cc:dd:ee:ff",
    "ip_address": "192.168.0.100",
    "snmp": {
      "snmp_v2c": {
        "community": "private"
      }
    },
    "pnm_parameters": {
      "tftp": {
        "ipv4": "192.168.0.200",
        "ipv6": "::1",
        "dest_dir": ""
      },
      "capture": {
        "channel_ids": []
      }
    }
  },
  "analysis": {
    "output": {
      "type": "json"
    },
    "plot": {
      "ui": {
        "theme": "dark"
      }
    }
  }
}
JSON

The JSON response will contain channel-estimation taps and related metadata, aligned with your CmDsOfdmChanEstimateCoef / analysis models.

Downstream OFDM FEC Summary

Endpoint:

• POST /docs/pnm/ds/ofdm/fecSummary/getCapture

Example:

curl -X POST "http://127.0.0.1:8000/docs/pnm/ds/ofdm/fecSummary/getCapture"   -H "Content-Type: application/json"   -d @- << 'JSON'
{
  "cable_modem": {
    "mac_address": "aa:bb:cc:dd:ee:ff",
    "ip_address": "192.168.0.100",
    "snmp": {
      "snmp_v2c": {
        "community": "private"
      }
    },
    "pnm_parameters": {
      "tftp": {
        "ipv4": "192.168.0.200",
        "ipv6": "::1",
        "dest_dir": ""
      },
      "capture": {
        "channel_ids": []
      }
    }
  },
  "analysis": {
    "output": {
      "type": "json"
    },
    "plot": {
      "ui": {
        "theme": "dark"
      }
    }
  }
}
JSON

The response payload typically includes per-profile and per-subcarrier summary counters (total codewords, corrected, uncorrectable, etc.).

Downstream OFDM Modulation Profile

Endpoint:

• POST /docs/pnm/ds/ofdm/modulationProfile/getCapture

Example:

curl -X POST "http://127.0.0.1:8000/docs/pnm/ds/ofdm/modulationProfile/getCapture"   -H "Content-Type: application/json"   -d @- << 'JSON'
{
  "cable_modem": {
    "mac_address": "aa:bb:cc:dd:ee:ff",
    "ip_address": "192.168.0.100",
    "snmp": {
      "snmp_v2c": {
        "community": "private"
      }
    },
    "pnm_parameters": {
      "tftp": {
        "ipv4": "192.168.0.200",
        "ipv6": "::1",
        "dest_dir": ""
      }
    }
  },
  "analysis": {
    "output": {
      "type": "json"
    },
    "plot": {
      "ui": {
        "theme": "dark"
      }
    }
  }
}
JSON

Downstream OFDM Constellation Display

Endpoint:

• POST /docs/pnm/ds/ofdm/constellationDisplay/getCapture

Constellation Display extends the same analysis block with additional plot options (such as display_cross_hair). The example below matches your UI fields:

curl -X POST "http://127.0.0.1:8000/docs/pnm/ds/ofdm/constellationDisplay/getCapture"   -H "Content-Type: application/json"   -d @- << 'JSON'
{
  "cable_modem": {
    "mac_address": "aa:bb:cc:dd:ee:ff",
    "ip_address": "192.168.0.100",
    "snmp": {
      "snmp_v2c": {
        "community": "private"
      }
    },
    "pnm_parameters": {
      "tftp": {
        "ipv4": "192.168.0.200",
        "ipv6": "::1",
        "dest_dir": ""
      }
    }
  },
  "analysis": {
    "type": "basic",
    "output": {
      "type": "json"
    },
    "plot": {
      "ui": {
        "theme": "dark"
      },
      "options": {
        "display_cross_hair": true
      }
    }
  },
  "capture_settings": {
    "modulation_order_offset": 0,
    "number_sample_symbol": 8192
  }
}
JSON

If you switch the output type to a plot/archive-oriented value in your OutputType enum, you can have this endpoint generate MatPlot reports instead of pure JSON.

Downstream Spectrum Analysis

Endpoint:

• POST /docs/pnm/ds/spectrumAnalysis/getCapture

Example:

curl -X POST "http://127.0.0.1:8000/docs/pnm/ds/spectrumAnalysis/getCapture"   -H "Content-Type: application/json"   -d @- << 'JSON'
{
  "cable_modem": {
    "mac_address": "aa:bb:cc:dd:ee:ff",
    "ip_address": "192.168.0.100",
    "snmp": {
      "snmp_v2c": {
        "community": "private"
      }
    },
    "pnm_parameters": {
      "tftp": {
        "ipv4": "192.168.0.200",
        "ipv6": "::1",
        "dest_dir": ""
      }
    }
  },
  "analysis": {
    "type": "basic",
    "output": {
      "type": "json"
    },
    "plot": {
      "ui": {
        "theme": "dark"
      }
    },
    "spectrum_analysis": {
      "moving_average": {
        "points": 10
      }
    }
  },
  "capture_parameters": {
    "inactivity_timeout": 60,
    "first_segment_center_freq": 300000000,
    "last_segment_center_freq": 900000000,
    "segment_freq_span": 1000000,
    "num_bins_per_segment": 256,
    "noise_bw": 150,
    "window_function": 1,
    "num_averages": 1,
    "spectrum_retrieval_type": 1
  }
}
JSON

The JSON response will contain spectrum sweep configuration and amplitude bins that map directly onto the CmSpectrumAnalysis / CmSpectrumAnalysisSnmp models.

Upstream OFDMA Capture Endpoints

Upstream OFDMA Pre-Equalization

Endpoint:

• POST /docs/pnm/us/ofdma/preEqualization/getCapture

Example:

curl -X POST "http://127.0.0.1:8000/docs/pnm/us/ofdma/preEqualization/getCapture"   -H "Content-Type: application/json"   -d @- << 'JSON'
{
  "cable_modem": {
    "mac_address": "aa:bb:cc:dd:ee:ff",
    "ip_address": "192.168.0.100",
    "snmp": {
      "snmp_v2c": {
        "community": "private"
      }
    },
    "pnm_parameters": {
      "tftp": {
        "ipv4": "192.168.0.200",
        "ipv6": "::1",
        "dest_dir": ""
      }
    }
  },
  "analysis": {
    "output": {
      "type": "json"
    },
    "plot": {
      "ui": {
        "theme": "dark"
      }
    }
  }
}
JSON

The response will include decoded upstream pre-equalizer taps which correspond to the CmUsOfdmaPreEqModel used by the parser examples.

Programming Notes

• When scripting against these endpoints, it is often convenient to template the common request body and just substitute MAC/IP/TFTP values.
• The same JSON payloads shown here can be used directly in Postman, Python requests, or any other HTTP client.
• For automation, you can combine these curl invocations with the parser examples in src/pypnm/examples/python/parsers/ to build end-to-end workflows:
• Trigger capture via FastAPI.
• Download or reference the PNM binary.
• Parse with a Cm* parser and feed into additional analysis utilities.