# Update Contacts From JSON

`gog contacts update` supports JSON input via `--from-file`, so you can update People API fields without adding new CLI flags.

## Usage

Update from a file:

```bash
gog contacts get people/c123456 --json > contact.json

# Edit contact.json (see notes below)
gog contacts update people/c123456 --from-file contact.json
```

Update from stdin:

```bash
gog contacts get people/c123456 --json | \
  jq '(.contact.urls //= []) | (.contact.urls += [{"value":"https://example.com","type":"profile"}])' | \
  gog contacts update people/c123456 --from-file -
```

## Input Formats

The command accepts:

- Wrapped (from `gog contacts get --json`): `{"contact": { ...person... }}`
- Direct Person object: `{ ...person... }`

## What Can Be Updated

`--from-file` updates only fields that the People API allows via `people.updateContact` `updatePersonFields`.

Practical rule: include only fields you want to change, at the top level of the JSON object (for example `urls`, `biographies`, `names`, `emailAddresses`, `phoneNumbers`, `addresses`, `organizations`, ...).

If the JSON contains unsupported fields (for `updateContact`), gog errors instead of silently ignoring them.

Notes:

- Some fields are “singleton” for contact sources. Don’t include more than one value for `biographies`, `birthdays`, `genders`, or `names`.
- If you update `memberships`, the Person must include contact group memberships or the API will error.

## Clearing Fields

Clearing list fields is supported by including the key with an empty value:

- Use `[]` to clear a list field (example: `"urls": []`)
- Use `null` to clear a list field (example: `"biographies": null`)

## Concurrency (ETags)

To avoid overwriting concurrent contact edits, gog compares the JSON etag with the current contact etag:

- If they mismatch, update fails with an etag error.
- Use `--ignore-etag` to apply your JSON changes to the latest version anyway.