initial commit

hive-watcher.js

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+/**
+ * Example way to use the dhive library to watch for podpings on the Hive blockchain.
+ */
+
+MEDIUM_PODCAST = "podcast"
+MEDIUM_AUDIOBOOK = "audiobook"
+MEDIUM_BLOG = "blog"
+MEDIUM_FILM = "film"
+MEDIUM_MUSIC = "music"
+MEDIUM_NEWSLETTER = "newsletter"
+MEDIUM_VIDEO = "video"
+
+PodpingMedium = [
+    MEDIUM_PODCAST,
+    MEDIUM_AUDIOBOOK,
+    MEDIUM_BLOG,
+    MEDIUM_FILM,
+    MEDIUM_MUSIC,
+    MEDIUM_NEWSLETTER,
+    MEDIUM_VIDEO,
+]
+
+REASON_LIVE = "live"
+REASON_LIVE_END = "liveEnd"
+REASON_UPDATE = "update"
+
+PodpingReason = [
+    REASON_LIVE,
+    REASON_LIVE_END,
+    REASON_UPDATE,
+]
+
+let lastBlockNumber = undefined
+
+/**
+ * Shuffles items in an array. Shuffles in place
+ *
+ * from https://stackoverflow.com/a/12646864
+ *
+ * @param array list of items to shuffle
+ */
+function shuffleArray(array) {
+    for (let i = array.length - 1; i > 0; i--) {
+        const j = Math.floor(Math.random() * (i + 1));
+        [array[i], array[j]] = [array[j], array[i]];
+    }
+}
+
+const addressList = [
+    "https://api.openhive.network",
+    "https://api.hive.blog",
+    "https://anyx.io",
+    "https://api.deathwing.me",
+]
+// shuffle list to try and spread the load across different endpoints since the first item is always used.
+shuffleArray(addressList)
+console.log(`Using API address "${addressList[0]}"`)
+const client = new dhive.Client(
+    addressList, {
+        // reducing timeout and threshold makes fall over to other API address happen faster
+        timeout: 6000, // in ms
+        failoverThreshold: 1,
+    }
+);
+
+let validAccounts = ['podping']
+
+/**
+ * Handle new block received
+ *
+ * @param block received block
+ */
+function handleBlock(block) {
+    try {
+        let timestamp = block.timestamp
+
+        for (let transaction of block.transactions) {
+            handleTransaction(transaction, timestamp)
+        }
+    } catch (error) {
+        console.error("error handling block")
+        console.error(error)
+    }
+}
+
+/**
+ * Handle transaction included in block
+ *
+ * @param transaction received transaction
+ * @param timestamp timestamp for block transaction is in
+ */
+function handleTransaction(transaction, timestamp) {
+    let blockNumber = transaction.block_num
+    let transactionId = transaction.transaction_id
+    lastBlockNumber = blockNumber
+
+    const block_num_span = document.getElementById("block_num");
+    block_num_span.innerText = blockNumber.toLocaleString()
+
+    for (let operation of transaction.operations) {
+        handleOperation(operation, timestamp, blockNumber, transactionId)
+    }
+}
+
+/**
+ * Handle operation included in transaction
+ *
+ * @param operation received operation
+ * @param timestamp timestamp for block operation is in
+ * @param blockNumber block number operation is in
+ * @param transactionId transaction operation is in
+ */
+function handleOperation(operation, timestamp, blockNumber, transactionId) {
+    let operationType = operation[0]
+    if (operationType === "custom_json") {
+        let post = operation[1]
+        handleCustomJsonPost(post, timestamp, blockNumber, transactionId)
+    }
+}
+
+/**
+ * Handle custom JSON post and check if desired type
+ *
+ * @param post received post in operation
+ * @param timestamp timestamp for block post is in
+ * @param blockNumber block number post is in
+ * @param transactionId transaction identifier post is in
+ */
+function handleCustomJsonPost(post, timestamp, blockNumber, transactionId) {
+    if (post.id === "podping" || post.id.startsWith("pp_")) {
+        handlePodpingPost(post, timestamp, blockNumber, transactionId)
+    }
+    // To include test posts
+    // else if (post.id === "podpingtest" || post.id.startsWith("pplt_")) {
+    //     handlePodpingPost(post, timestamp, blockNumber, transactionId)
+    // }
+}
+
+
+/**
+ * Handle PodPing post
+ *
+ * @param post received post in operation
+ * @param timestamp timestamp for block post is in
+ * @param blockNumber block number post is in
+ * @param transactionId transaction identifier post is in
+ */
+function handlePodpingPost(post, timestamp, blockNumber, transactionId) {
+    if (!this.isAccountAllowed(post.required_posting_auths))
+        return
+
+    let postJson = JSON.parse(post.json)
+
+    let version = postJson.version || postJson.v
+    let updateReason = postJson.reason || postJson.r || postJson.type
+    let medium = postJson.medium
+
+    if (version === "1.0") {
+        if (!(PodpingReason.includes(updateReason) && PodpingMedium.includes(medium))) {
+            return
+        }
+    } else {
+        // fallback to any possible
+        // old posts didn't include an update type so still accept them
+        if (updateReason !== undefined && updateReason !== "feed_update" && updateReason !== 1)
+            return
+    }
+
+    let iris = postJson.iris || []
+    let urls = postJson.urls || []
+    if (urls) {
+        iris = iris.concat(urls)
+    }
+    if (postJson.url) {
+        iris = [postJson.url]
+    }
+
+    const list = document.getElementById("posts");
+
+    // add ping
+    const transactionMessage = `Feed updated(s) - ${timestamp} - ${blockNumber} - ${transactionId} - ${updateReason} - ${medium}`;
+    console.log(transactionMessage)
+
+    const item = document.createElement("li");
+    item.appendChild(document.createTextNode(transactionMessage))
+    list.appendChild(item)
+
+    const subList = document.createElement("ul")
+    item.appendChild(subList)
+    for (let iri of iris) {
+        console.log(`  - ${iri}`)
+
+        const subItem = document.createElement("li");
+
+        const linkItem = document.createElement("a")
+        linkItem.href = iri
+        linkItem.target = "_blank"
+        linkItem.appendChild(document.createTextNode(iri))
+        subItem.appendChild(linkItem)
+
+        subList.appendChild(subItem)
+    }
+}
+
+/**
+ * Checks if account making PodPing is allowed
+ *
+ * @param required_posting_auths account used to make PodPing post
+ * @returns true if account is valid
+ */
+function isAccountAllowed(required_posting_auths) {
+    // check if valid user
+    let postingAuths = new Set(required_posting_auths)
+    let accounts = new Set(validAccounts)
+    let intersect = new Set()
+    for (let x of accounts) {
+        if (postingAuths.has(x))
+            intersect.add(x)
+    }
+    // if accounts don't overlap, skip post
+    return intersect.size !== 0
+}
+
+client.database.call('get_following', [validAccounts[0], null, 'blog', 100])
+    .then(
+        /**
+         * Get all accounts that are accepted as a valid PodPing poster
+         *
+         * @param followers list of follower objects
+         */
+        function (followers) {
+            for (let follower of followers) {
+                validAccounts = validAccounts.concat(follower.following)
+            }
+        }
+    )
+    .then(
+        startStream
+    )
+;
+
+function startStream(blockNumber = undefined) {
+    // can pass the block number to start searching from. By default, uses the current block
+    // note: using mode BlockchainMode.Latest does not seem to return data using `getOperationsStream` so
+    // `getBlockStream` is used instead and transactions are parsed by block
+    client.blockchain.getBlockStream({
+        from: blockNumber,
+        mode: dhive.BlockchainMode.Latest
+    })
+        .on('data', handleBlock)
+        .on('error',
+            function (error) {
+                console.error('Error occurred parsing stream')
+                console.error(error)
+                // Note: when an error occurs, the `end` event is emitted (see below)
+            }
+        )
+        .on('end',
+            function () {
+                console.log('Reached end of stream')
+                // Note: this restart the stream
+                startStream(lastBlockNumber);
+            }
+        );
+
+}

index.html

@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<html lang="en">
+    <head>
+        <meta charset="utf-8"/>
+
+        <title>Hive Watcher</title>
+
+        <script src="https://unpkg.com/@hiveio/[email protected]/dist/dhive.js"></script>
+        <script src="hive-watcher.js"></script>
+    </head>
+    <body>
+        <noscript>This site requires JavaScript to run.</noscript>
+        <h1>Hive Posts</h1>
+        <p>Parsing block #<span id="block_num">0</span></p>
+        <ol id="posts"></ol>
+    </body>
+</html>