winsoroaks•2w ago

How to properly combine a Convex query with an action?

I'm trying to implement a query that needs to fetch some encrypted data and decrypt it using AWS KMS. However, I'm running into a TypeScript error where ctx.runAction is not available in the query context. Here's a simplified version of what I'm trying to do:

export const queryEncryptedData = query({
  args: { id: v.string() },
  handler: async (ctx, args) => {
    // 1. First fetch the encrypted data
    const data = await ctx.db
      .query("myTable")
      .withIndex("by_id", q => q.eq("id", args.id))
      .first()
    if (!data) return undefined

    // 2. Then try to decrypt the sensitive fields
    // This is where we get the error:
    // Property 'runAction' does not exist on type 'QueryCtx'
    const decryptedItems = await Promise.all(
      data.items.map(async (item) => ({
        ...item,
        value: await ctx.runAction(internal.kms.decryptData, {
          data: item.encryptedValue?.data,
          key: item.encryptedValue?.key,
          iv: item.encryptedValue?.iv,
        })
      }))
    )

    return {
      items: data.items.map(item => ({
        ...item,
        // Need to return the decrypted value here
      }))
    }
  }
})

export const queryEncryptedData = query({
  args: { id: v.string() },
  handler: async (ctx, args) => {
    // 1. First fetch the encrypted data
    const data = await ctx.db
      .query("myTable")
      .withIndex("by_id", q => q.eq("id", args.id))
      .first()
    if (!data) return undefined

    // 2. Then try to decrypt the sensitive fields
    // This is where we get the error:
    // Property 'runAction' does not exist on type 'QueryCtx'
    const decryptedItems = await Promise.all(
      data.items.map(async (item) => ({
        ...item,
        value: await ctx.runAction(internal.kms.decryptData, {
          data: item.encryptedValue?.data,
          key: item.encryptedValue?.key,
          iv: item.encryptedValue?.iv,
        })
      }))
    )

    return {
      items: data.items.map(item => ({
        ...item,
        // Need to return the decrypted value here
      }))
    }
  }
})

is the only option to do useEffect in the front end component?

7 Replies

Convex Bot•2w ago

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erquhart•2w ago

Yeah you'll want to run the action when the query changes, both from the client. An updatedAt timestamp field on the table with the encrypted data would help, so you can just query that and run the effect when it changes.

winsoroaksOP•2w ago

thanks! this seems kinda messy 😦

erquhart•2w ago

I can see that. But if you're fetching data on the server and you cannot store it anywhere due to it's sensitive nature, I don't know how much cleaner you're going to get than this in any reactive framework. If the reactivity isn't important you could just run an action to get everything at once, but guessing you want it reactive

winsoroaksOP•2w ago

if i dont want it to be reactive, can i run the action without storing the decrypted data in the table for fetching?

erquhart•2w ago

Yep, you would call the action from the client, and in the action you can await ctx.runQuery() for the encrypted data, decrypt it, and return queries can't await actions but actions can await anything

winsoroaksOP•2w ago

got it. thanks!

How to properly combine a Convex query with an action?

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