# Upload assets

Register an asset, wait until it is active, then reference it with asset:// in generation requests.

An asset is an image, video or audio file registered with the platform. Register it once and reference it in as many generation requests as you like.

## When to use assets

An image, video or audio input of a generation request comes from one of three sources: an HTTPS link, a base64 data URI or a registered asset. Registering pays off when you use the same file again and again; for a single use, put the link in the request. The rules of each source are on [Generate a video](./api-docs-en-video-generate.md#sources).

## Register an asset

Send the public HTTPS address, the media type and the model to `POST /v1/assets`. Registration needs an `Idempotency-Key`, and the API key needs `service.use` permission.

```bash
IDEMPOTENCY_KEY=${IDEMPOTENCY_KEY:-$(uuidgen)}
printf '%s\n' "Save IDEMPOTENCY_KEY for retries: ${IDEMPOTENCY_KEY}" >&2
curl --request POST "${CHENVOYA_BASE_URL}/v1/assets" \
  --header "Authorization: Bearer ${CHENVOYA_API_KEY}" \
  --header "Idempotency-Key: ${IDEMPOTENCY_KEY}" \
  --header 'Content-Type: application/json' \
  --data '{
  "url": "https://images.example.test/reference.png",
  "media_type": "image",
  "model": "dreamina-seedance-2-0-260128",
  "name": "reference"
}'
```

```python
import urllib.request
import urllib.parse
import json
import os
import sys
import re
import uuid

key = os.environ["CHENVOYA_API_KEY"].strip()
if not key or re.search(r"[\x00-\x1f\x7f-\x9f]", key):
    sys.exit("Set CHENVOYA_API_KEY to a non-empty value without control characters")
base = os.environ["CHENVOYA_BASE_URL"].rstrip("/")
headers = {"Authorization": "Bearer " + key}
idempotency = os.environ.get("IDEMPOTENCY_KEY") or str(uuid.uuid4())
print("Save IDEMPOTENCY_KEY for retries: " + idempotency, file=sys.stderr)
headers["Idempotency-Key"] = idempotency
path = "/v1/assets"
body_text = "{\"url\":\"https://images.example.test/reference.png\",\"media_type\":\"image\",\"model\":\"dreamina-seedance-2-0-260128\",\"name\":\"reference\"}"
headers["Content-Type"] = "application/json"
body = json.dumps(json.loads(body_text)).encode("utf-8")
request = urllib.request.Request(base + path, data=body, headers=headers, method="POST")
try:
    with urllib.request.urlopen(request) as response:
        print(response.read().decode("utf-8"))
except urllib.request.HTTPError as error:
    print(error.read().decode("utf-8"))
    sys.exit(1)
```

```javascript
// Needs Node.js 20 or later; save it as a .mjs file and run it.
const key = process.env.CHENVOYA_API_KEY?.trim();
if (!key || /[\x00-\x1f\x7f-\x9f]/.test(key)) {
  console.error("Set CHENVOYA_API_KEY to a non-empty value without control characters");
  process.exit(1);
}
const base = process.env.CHENVOYA_BASE_URL;
if (!base) throw new Error("Set CHENVOYA_BASE_URL");
const headers = {Authorization: `Bearer ${key}`};
const idempotency = process.env.IDEMPOTENCY_KEY || crypto.randomUUID();
console.error("Save IDEMPOTENCY_KEY for retries: " + idempotency);
headers["Idempotency-Key"] = idempotency;
const path = "/v1/assets";
let bodyText = "{\"url\":\"https://images.example.test/reference.png\",\"media_type\":\"image\",\"model\":\"dreamina-seedance-2-0-260128\",\"name\":\"reference\"}";
headers["Content-Type"] = "application/json";
const body = JSON.stringify(JSON.parse(bodyText));
const response = await fetch(base.replace(/\/$/, "") + path, {method: "POST", headers, body: body});
console.log(await response.text());
if (!response.ok) process.exitCode = 1;
```

```go
package main

import (
	"crypto/rand"
	"fmt"
	"io"
	"net/http"
	"os"
	"regexp"
	"strings"
)

func main() {
	key := strings.TrimSpace(os.Getenv("CHENVOYA_API_KEY"))
	if key == "" || regexp.MustCompile(`[\x00-\x1f\x7f-\x9f]`).MatchString(key) {
		fail("Set CHENVOYA_API_KEY to a non-empty value without control characters")
	}
	base := strings.TrimRight(os.Getenv("CHENVOYA_BASE_URL"), "/")
	if base == "" {
		fail("Set CHENVOYA_BASE_URL")
	}
	path := "/v1/assets"
	bodyText := "{\"url\":\"https://images.example.test/reference.png\",\"media_type\":\"image\",\"model\":\"dreamina-seedance-2-0-260128\",\"name\":\"reference\"}"
	request, err := http.NewRequest("POST", base+path, strings.NewReader(bodyText))
	if err != nil {
		fail(err.Error())
	}
	request.Header.Set("Authorization", "Bearer "+key)
	request.Header.Set("Content-Type", "application/json")
	idempotency := os.Getenv("IDEMPOTENCY_KEY")
	if idempotency == "" {
		idempotency = newOperationKey()
	}
	fmt.Fprintln(os.Stderr, "Save IDEMPOTENCY_KEY for retries: "+idempotency)
	request.Header.Set("Idempotency-Key", idempotency)
	response, err := http.DefaultClient.Do(request)
	if err != nil {
		fail(err.Error())
	}
	text, err := io.ReadAll(response.Body)
	response.Body.Close()
	if err != nil {
		fail(err.Error())
	}
	fmt.Println(string(text))
	if response.StatusCode < 200 || response.StatusCode > 299 {
		os.Exit(1)
	}
}

func fail(message string) {
	fmt.Fprintln(os.Stderr, message)
	os.Exit(1)
}

// newOperationKey returns a random UUID; save it to retry with the same value.
func newOperationKey() string {
	var b [16]byte
	if _, err := rand.Read(b[:]); err != nil {
		fail(err.Error())
	}
	b[6] = b[6]&0x0f | 0x40
	b[8] = b[8]&0x3f | 0x80
	return fmt.Sprintf("%x-%x-%x-%x-%x", b[0:4], b[4:6], b[6:8], b[8:10], b[10:16])
}
```

After acceptance the platform downloads and checks the file in the background; the `Location` response header is the path to read.

```json
{
  "asset_id": "ast-11111111111111111111111111111111",
  "status": "processing"
}
```

## Read the status

Read `GET /v1/assets/{asset_id}` until the status is no longer `processing`:

| Status | Meaning |
| --- | --- |
| `processing` | Being downloaded and checked; it cannot be referenced yet. |
| `active` | Ready to reference; size and digest are returned, with the dimensions of images and videos and the duration of audio and video. |
| `unavailable` | Cannot be used; `failure_reason` says why. |

```bash
curl --request GET "${CHENVOYA_BASE_URL}/v1/assets/${ASSET_ID}" \
  --header "Authorization: Bearer ${CHENVOYA_API_KEY}"
```

```python
import urllib.request
import urllib.parse
import json
import os
import sys
import re
import uuid

key = os.environ["CHENVOYA_API_KEY"].strip()
if not key or re.search(r"[\x00-\x1f\x7f-\x9f]", key):
    sys.exit("Set CHENVOYA_API_KEY to a non-empty value without control characters")
base = os.environ["CHENVOYA_BASE_URL"].rstrip("/")
headers = {"Authorization": "Bearer " + key}
ASSET_ID = os.environ["ASSET_ID"]
if not re.fullmatch("^ast-[0-9a-f]{32}$", ASSET_ID):
    sys.exit("Set ASSET_ID to the ID from the creation response")
path = "/v1/assets/{asset_id}".replace("{asset_id}", urllib.parse.quote(ASSET_ID, safe=""))
request = urllib.request.Request(base + path, data=None, headers=headers, method="GET")
try:
    with urllib.request.urlopen(request) as response:
        print(response.read().decode("utf-8"))
except urllib.request.HTTPError as error:
    print(error.read().decode("utf-8"))
    sys.exit(1)
```

```javascript
// Needs Node.js 20 or later; save it as a .mjs file and run it.
const key = process.env.CHENVOYA_API_KEY?.trim();
if (!key || /[\x00-\x1f\x7f-\x9f]/.test(key)) {
  console.error("Set CHENVOYA_API_KEY to a non-empty value without control characters");
  process.exit(1);
}
const base = process.env.CHENVOYA_BASE_URL;
if (!base) throw new Error("Set CHENVOYA_BASE_URL");
const headers = {Authorization: `Bearer ${key}`};
const ASSET_ID = process.env.ASSET_ID;
if (!ASSET_ID) throw new Error("Set ASSET_ID");
if (typeof ASSET_ID !== "string" || (new RegExp("^ast-[0-9a-f]{32}$")).exec(ASSET_ID)?.[0] !== ASSET_ID) throw new Error("Set ASSET_ID to the ID from the creation response");
const path = "/v1/assets/{asset_id}".replace("{asset_id}", encodeURIComponent(ASSET_ID));
const response = await fetch(base.replace(/\/$/, "") + path, {method: "GET", headers, body: undefined});
console.log(await response.text());
if (!response.ok) process.exitCode = 1;
```

```go
package main

import (
	"fmt"
	"io"
	"net/http"
	"net/url"
	"os"
	"regexp"
	"strings"
)

func main() {
	key := strings.TrimSpace(os.Getenv("CHENVOYA_API_KEY"))
	if key == "" || regexp.MustCompile(`[\x00-\x1f\x7f-\x9f]`).MatchString(key) {
		fail("Set CHENVOYA_API_KEY to a non-empty value without control characters")
	}
	base := strings.TrimRight(os.Getenv("CHENVOYA_BASE_URL"), "/")
	if base == "" {
		fail("Set CHENVOYA_BASE_URL")
	}
	assetID := os.Getenv("ASSET_ID")
	if assetID == "" {
		fail("Set ASSET_ID")
	}
	if !regexp.MustCompile(`\A(?:ast-[0-9a-f]{32})\z`).MatchString(assetID) {
		fail("Set ASSET_ID to the ID from the creation response")
	}
	path := strings.Replace("/v1/assets/{asset_id}", "{asset_id}", url.PathEscape(assetID), 1)
	request, err := http.NewRequest("GET", base+path, nil)
	if err != nil {
		fail(err.Error())
	}
	request.Header.Set("Authorization", "Bearer "+key)
	response, err := http.DefaultClient.Do(request)
	if err != nil {
		fail(err.Error())
	}
	text, err := io.ReadAll(response.Body)
	response.Body.Close()
	if err != nil {
		fail(err.Error())
	}
	fmt.Println(string(text))
	if response.StatusCode < 200 || response.StatusCode > 299 {
		os.Exit(1)
	}
}

func fail(message string) {
	fmt.Fprintln(os.Stderr, message)
	os.Exit(1)
}
```

## Reference an asset

Write `asset://` and the asset ID in the `url` of an `image_url`, `video_url` or `audio_url` item. An asset registered for one model can also be used by requests for other compatible models.

- Referencing an asset that is still processing returns `409 asset_not_ready`; once it is `active`, retry with the same `Idempotency-Key`.
- An asset of another team, an unknown one and a deleted one all return `asset_not_found`.
- One request cannot mix `asset://` references with HTTPS links or base64 data.

## Addresses and allowances

- The source must be a public HTTPS address of at most 2048 bytes without user information; an unsafe destination returns `400 source_url_not_allowed`.
- When your team's storage allowance is used up the answer is `429 asset_storage_quota_exceeded`; when intake capacity is limited it is `429 asset_intake_rate_limit_exceeded`: retry later.

## Next steps

- [Generate a video](./api-docs-en-video-generate.md): Requests for text to video, first frames, first and last frames, reference images and reference media.
- [Register an asset](./api-docs-en-api-assets-create.md): Requires service.use.
- [The asset object](./api-docs-en-api-assets-object.md): For active assets, size_bytes and sha256 are required.