begin adding blockheader type

packages/transport-http/src/subscribe/handlers/block-headers.ts

@@ -0,0 +1,93 @@
+import {SdkTransport} from "@onflow/typedefs"
+import {BlockArgsModel, createSubscriptionHandler} from "./types"
+
+type BlockHeaderArgs =
+  SdkTransport.SubscriptionArguments<SdkTransport.SubscriptionTopic.BLOCK_HEADERS>
+
+type BlockHeaderData =
+  SdkTransport.SubscriptionData<SdkTransport.SubscriptionTopic.BLOCK_HEADERS>
+
+type BlockHeaderArgsModel = BlockArgsModel
+
+type BlockHeaderDataModel = {
+  // TODO: We do not know the data model types yet
+  header: {
+    id: string
+    height: number
+    timestamp: string
+    chain_id: string
+    parent_id: string
+    collection_guarantees: {
+      collection_id: string
+      signer_ids: string[]
+    }[]
+    block_seals: {
+      block_id: string
+      result_id: string
+    }[]
+  }
+}
+
+export const blockHeaderHandler = createSubscriptionHandler<{
+  Topic: SdkTransport.SubscriptionTopic.BLOCK_HEADERS
+  Args: BlockHeaderArgs
+  Data: BlockHeaderData
+  ArgsModel: BlockHeaderArgsModel
+  DataModel: BlockHeaderDataModel
+}>({
+  topic: SdkTransport.SubscriptionTopic.BLOCK_HEADERS,
+  createSubscriber: (initialArgs, onData, onError) => {
+    let resumeArgs: BlockHeaderArgs = {
+      ...initialArgs,
+    }
+
+    return {
+      sendData(data: BlockHeaderDataModel) {
+        // Parse the raw data
+        const parsedData: BlockHeaderData = {
+          blockHeader: {
+            id: data.header.id,
+            height: data.header.height,
+            timestamp: data.header.timestamp,
+            chainId: data.header.chain_id,
+          },
+        }
+
+        // Update the resume args
+        resumeArgs = {
+          blockStatus: resumeArgs.blockStatus,
+          startBlockHeight: data.header.height + 1,
+        }
+
+        onData(parsedData)
+      },
+      sendError(error: Error) {
+        onError(error)
+      },
+      encodeArgs(args: BlockHeaderArgs) {
+        let encodedArgs: BlockHeaderArgsModel = {
+          block_status: args.blockStatus,
+        }
+
+        if ("startBlockHeight" in args) {
+          return {
+            ...encodedArgs,
+            start_block_height: args.startBlockHeight,
+          }
+        }
+
+        if ("startBlockId" in args) {
+          return {
+            ...encodedArgs,
+            start_block_id: args.startBlockId,
+          }
+        }
+
+        return encodedArgs
+      },
+      get connectionArgs() {
+        return resumeArgs
+      },
+    }
+  },
+})

packages/transport-http/src/subscribe/subscribe.ts

@@ -2,8 +2,13 @@ import {SdkTransport} from "@onflow/typedefs"
 import {SubscriptionManager} from "./subscription-manager"
 import {blocksHandler} from "./handlers/blocks"
 import {blockDigestsHandler} from "./handlers/block_digests"
+import {blockHeaderHandler} from "./handlers/block-headers"
 
-const SUBSCRIPTION_HANDLERS = [blocksHandler, blockDigestsHandler]
+const SUBSCRIPTION_HANDLERS = [
+  blocksHandler,
+  blockDigestsHandler,
+  blockHeaderHandler,
+]
 
 // Map of SubscriptionManager instances by access node URL
 let subscriptionManagerMap: Map<

packages/typedefs/src/index.ts

@@ -137,6 +137,66 @@ export type BlockDigest = {
    */
   timestamp: string
 }
+/**
+ * Header contains all meta-data for a block, as well as a hash representing
+ * the combined payload of the entire block. It is what consensus nodes agree
+ * on after validating the contents against the payload hash.
+ */
+// TODO: We do not know the data model types yet and are waiting for the AN team.
+export type BlockHeader = {
+  /**
+   * TA chain-specific value to prevent replay attacks.
+   */
+  chainId: string
+  /**
+   * - The id of the block
+   */
+  id: string
+  /**
+   * - The id of the parent block
+   */
+  parentId: string
+  /**
+   * - The height of the block
+   */
+  height: number
+  /**
+   * - The hash of the block's payload
+   */
+  payloadHash: string
+  /**
+   * - The timestamp of the block
+   */
+  timestamp: string
+  /**
+   * - The view of the block
+   */
+  view: number
+  /**
+   * - The view of the parent block
+   */
+  parentView: number
+  /**
+   * - The bitvector that represents all the voters for the parent block
+   */
+  parentVoterIndices: string
+  /**
+   * - The aggregated signature over the parent block
+   */
+  parentVoterSigData: string
+  /**
+   * - The proposer id of the block
+   */
+  proposerId: string
+  /**
+   * - The aggregated signature over the block
+   */
+  proposerSigData: string
+  /**
+   * - The last view timeout certificate
+   */
+  lastViewTC: any
+}
 export type CompositeSignature = {
   /**
    * - A type identifier used internally by FCL

packages/typedefs/src/sdk-transport/subscriptions.ts

@@ -1,4 +1,4 @@
-import {Block, BlockDigest} from ".."
+import {Block, BlockDigest, BlockHeader} from ".."
 
 export type SubscriptionSchema = {
   [SubscriptionTopic.BLOCKS]: SchemaItem<
@@ -13,11 +13,18 @@ export type SubscriptionSchema = {
       blockDigest: BlockDigest
     }
   >
+  [SubscriptionTopic.BLOCK_HEADERS]: SchemaItem<
+    BlockArgs,
+    {
+      blockHeader: BlockHeader
+    }
+  >
 }
 
 export enum SubscriptionTopic {
   BLOCKS = "blocks",
   BLOCK_DIGESTS = "block_digests",
+  BLOCK_HEADERS = "block_headers",
 }
 
 type BlockArgs =