KV Operations

The KV Operations block reads and writes single keys in a key-value store. Use it to cache an expensive result, keep a short-lived token, count something, or hold state between requests.

Pick the operation you want and the block shows only the fields that operation needs.

Inputs

• Connection: The KV store integration to use — see KV Stores.
• Operation: Get, Set, or Delete.
• Key: The key to work with. Accepts a JS expression, so the key can depend on the request, for example js:return "user:" + getRouteParam("id").

Depending on the operation, you also get:

Operation	Extra fields
Get	Parse JSON
Set	Use Param, Value, TTL (seconds)
Delete	none

What each operation returns

Operation	Output
Get	The stored value, or null when the key does not exist
Set	true
Delete	true

Get

By default a value comes back exactly as it was stored — as text.

Tick Parse JSON when the key holds a JSON object or array and you want to work with it as real data in later blocks, rather than a string.

// stored value: {"id":7,"name":"ada"}
// Parse JSON off -> '{"id":7,"name":"ada"}'  (a string)
// Parse JSON on  -> { id: 7, name: "ada" }   (an object)

A missing key stays null

If the key isn't there, the output is null whether or not Parse JSON is on. Nothing is parsed, so you can always check for null to mean "not cached yet".

WARNING

With Parse JSON on, a value that is not valid JSON fails the block instead of quietly handing the next block a string. If a key might hold plain text, leave the option off and parse it yourself in a JS Runner.

Set

Value is what gets stored. It accepts a JS expression, and anything that isn't text is stored as JSON automatically — so you can hand it an object without converting it first.

Tick Use Param to store the previous block's output instead of typing a value. This is the common shape for caching: fetch something, then cache exactly what you fetched.

TTL (seconds) sets how long the key lives. Leave it empty (or 0) to store the key with no expiry.

TTL	Meaning
empty or 0	Keep the key until something deletes it
60	Expire the key after 60 seconds

Delete

Removes the key. Deleting a key that was never there is not an error — the output is still true.

Example: cache an expensive lookup

A typical read-through cache needs three of these blocks:

1. KV Operations — Get the key js:return "user:" + getRouteParam("id"), with Parse JSON on.
2. If Condition — check whether that output is null.
   • Not null: the value was cached, go straight to your Response.
   • null: fetch the record with DB Get Single, then KV Operations again — Set, same key, Use Param ticked, TTL 300 — and respond.

Notes

• Keys and values are text at the storage level. Parse JSON on the way out and automatic JSON encoding on the way in are conveniences around that.
• Both Redis and Memcached support everything on this block, so a workflow built against one still works if you point the connection at the other.
• For anything beyond get, set, and delete — counters, expiry on an existing key, hashes, lists — use the KV Raw Connection block.
• Tick Save output to variable to keep the result under outputs.<name> for later blocks.