Query and retrieve data

Continue from your first query in the same terminal, folder, and signed-in session. Every command here is read-only. The examples still use the pinned package and require no global installation.

Search for a flow by description

Save the complete JSON below as flow-search.request.json in a text editor using UTF-8. You can also download the example request.

{
  "query": "Carbon dioxide emission to air",
  "filter": {
    "flowType": "Elementary flow",
    "asInput": false
  }
}

query describes the flow you need; filter is optional. This example selects elementary flows (Elementary flow). asInput: false does not apply the input-specific restriction; it does not guarantee output-only results, so check the actual classification and intended use. The query text is not an instruction to change data.

First run a dry run to inspect the destination and request, then make the real query:

Run commands one at a time. Immediately afterward, use echo $? on macOS/Linux or $LASTEXITCODE in PowerShell 7 to read the exit code; later commands can replace it. Except for explicitly expected sign-in/error demonstrations, stop on a nonzero code and resolve the error before continuing.

pnpm dlx --package=@tiangong-lca/cli@0.1.8 tiangong-lca search flow --input ./flow-search.request.json --dry-run --json

pnpm dlx --package=@tiangong-lca/cli@0.1.8 tiangong-lca search flow --input ./flow-search.request.json --json > flow-results.json

--dry-run returns dryRun: true and a masked request. It makes no business query and does not prove that sign-in or access works. Only the second command contacts the platform; search can take longer than an ordinary list request.

Distinguish no matches from a failed request

Each result uses id and version for identity; the full flow is under json.flowDataSet. Within it, find the name at flowInformation.dataSetInformation.name.baseName; language text uses @xml:lang and #text. Use only fields actually returned.

A successful nonempty result is { "data": [...] }. No matches may be represented as [] or { "data": [] }. An empty array alone is not a failure, and retrieval order is not proof that a record fits your study.

Check the exit code before interpreting JSON. If nothing matches, retain the original request and try a more precise name or chemical identifier, or relax filter step by step. For 400, check query and JSON syntax. For 401/403, check identity and permissions. 500 means a server-side search failure, not “the database contains no such data.”

Before choosing a candidate, check its flow type, name, classification, geography, and unit/flow property against your study. Keep the original request and response, report the actual result count, and do not ask an AI to invent missing records.

Retrieve one complete process by ID

Open processes.json from the previous tutorial. Select one item in rows and copy its id and version. Replace PROCESS_ID and DATASET_VERSION below; these words are not real identifiers.

If the public list succeeds but is empty, your first-query task is still complete. Skip this section’s process get until a real id/version is available and do the flow-search exercise above instead. Do not repeatedly sign in or invent IDs.

pnpm dlx --package=@tiangong-lca/cli@0.1.8 tiangong-lca process get --id PROCESS_ID --version DATASET_VERSION --json > process.json

status: resolved_remote_process confirms a retrieved process. requested_version records your request, resolved_version is what was actually returned, resolution explains the lookup, and process contains the full data. An unavailable or missing requested version can fall back to the latest accessible version. For an exact citation, verify that the requested and resolved versions match; exit code 0 is not enough.

Choose listing, search, or pagination

Pagination spans requests; it is not a transaction snapshot of one instant. Do not start with --all: bound the result and inspect it first. Default ordering is id.asc,version.asc; for recently updated records, explicitly pass --order modified_at.desc,id.asc,version.asc.

Next: Validate local data and read reports needs no online sign-in. To have an AI perform the same search, follow Your first Skills task.