Set HTTP Header
The Set HTTP Header block adds one header to the response, like Cache-Control or X-Request-Id. Your data passes through it untouched.
When to use it
- Tell the caller or a cache how to treat the answer:
Cache-Control,Content-Language. - Add your own tracking header, like
X-Request-Id. - Don't use it for cookies. Use Set HTTP Cookie.
- Don't use it to send a header to another service. Put it in the Headers field of HTTP Request.
Inputs
| Field | Required | Default | What it does |
|---|---|---|---|
| Mode | No | Single | Single handles one value. Multiple handles a list of rows, see below. |
| Name | Yes | none | The header name, for example Cache-Control. Can be a JS expression. |
| Value | Yes | none | The header value, for example no-store. Can be a JS expression. |
Outputs
| Handle | When it is used |
|---|---|
| Next (right) | Always. The next block receives exactly what this block received. |
Example
Stop caches from keeping the answer.
| Name | Value |
|---|---|
Cache-Control | no-store |
The response that the Response block sends carries the header Cache-Control: no-store.
Single or Multiple
Pick Multiple to set several response headers in one block. Each row has a Name and a Value.
- Rows run from top to bottom.
inputis the previous block's output for every row. - If two rows use the same name, the later row wins.
- The block still passes its
inputthrough unchanged, as in Single mode.
| Name | Value |
|---|---|
Cache-Control | no-store |
X-Request-Id | js:return input.id; |
How it behaves
- The header is sent with the final response. Put the block anywhere before the Response block.
- Data passes through. The block does not change
input. - Setting the same name again replaces the earlier value.
- It only works for API routes. A workflow has no caller to send a header to.
Related blocks
- Set HTTP Cookie: send a cookie.
- Response: sends the final answer, with the headers you set.
- Get HTTP Header: read a header from the request.