<!DOCTYPE html> <html class=""> <head> <meta charset="utf-8"> <title>Pagination in the API</title> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta property="description" content="How to fetch results from large lists of objects."> <meta property="og:title" content="Pagination in the API"> <meta property="og:image" content="4dd378cd0f58b0b820"> <meta property="og:description" content="How to fetch results from large lists of objects."> <link rel="icon" type="image/svg+xml" href="/img/website_icon.svg?4"> <link rel="apple-touch-icon" sizes="180x180" href="/img/apple-touch-icon.png"> <link rel="icon" type="image/png" sizes="32x32" href="/img/favicon-32x32.png"> <link rel="icon" type="image/png" sizes="16x16" href="/img/favicon-16x16.png"> <link rel="alternate icon" href="/img/favicon.ico" type="image/x-icon" /> <link href="/css/bootstrap.min.css?3" rel="stylesheet"> <link href="/css/telegram.css?236" rel="stylesheet" media="screen"> <style> </style> </head> <body class="preload"> <div class="dev_page_wrap"> <div class="dev_page_head navbar navbar-static-top navbar-tg"> <div class="navbar-inner"> <div class="container clearfix"> <ul class="nav navbar-nav navbar-right hidden-xs"><li class="navbar-twitter"><a href="https://twitter.com/telegram" target="_blank" data-track="Follow/Twitter" onclick="trackDlClick(this, event)"><i class="icon icon-twitter"></i><span> Twitter</span></a></li></ul> <ul class="nav navbar-nav"> <li><a href="//telegram.org/">Home</a></li> <li class="hidden-xs"><a href="//telegram.org/faq">FAQ</a></li> <li class="hidden-xs"><a href="//telegram.org/apps">Apps</a></li> <li class="active"><a href="/api">API</a></li> <li class=""><a href="/mtproto">Protocol</a></li> <li class=""><a href="/schema">Schema</a></li> </ul> </div> </div> </div> <div class="container clearfix"> <div class="dev_page"> <div id="dev_page_content_wrap" class=" "> <div class="dev_page_bread_crumbs"><ul class="breadcrumb clearfix"><li><a href="/api" >API</a></li><i class="icon icon-breadcrumb-divider"></i><li><a href="/api/offsets" >Pagination in the API</a></li></ul></div> <h1 id="dev_page_title">Pagination in the API</h1> <div id="dev_page_content"><!-- scroll_nav --> <p>Lots of Telegram API methods provide access to potentially large lists of objects, which requires pagination.</p> <p>In order to fetch only relevant subset of results for each request there is a number of available input parameters. Here is a list in order how they are applied in API.</p> <p>Typically, results are returned in reverse chronological order with descending object ID values.</p> <h3><a class="anchor" name="limit-parameter" href="#limit-parameter"><i class="anchor-icon"></i></a><code>limit</code> parameter</h3> <p>A limit on the number of objects to be returned, typically between 1 and 100. When 0 is provided the limit will often default to an intermediate value like ~20.</p> <h3><a class="anchor" name="offset-based-pagination" href="#offset-based-pagination"><i class="anchor-icon"></i></a><code>offset</code>-based pagination</h3> <p>For a few methods with mostly static data this parameter allows to skip <code>offset</code> elements from the beginning of list; negative values are ignored.</p> <h3><a class="anchor" name="offset-id-based-pagination" href="#offset-id-based-pagination"><i class="anchor-icon"></i></a><code>offset_id</code>-based pagination</h3> <p>For most methods where results are real-time data (e.g. any chat history) <code>offset</code> value is not passed directly. Instead it is calculated from the passed <code>offset_id</code> and <code>add_offset</code> parameter values as <code>offsetFromID(offset_id) + add_offset</code>, where <code>offsetFromID(offset_id)</code> is a number of results from the beginning of list up to the result with ID <code>offset_id</code>, inclusive.</p> <p>Sample use cases:</p> <ul> <li>Loading 20 messages, older than message with ID <code>MSGID</code>:</li> </ul> <pre><code>messages.getHistory({offset_id: MSGID, add_offset: 0, limit: 20})</code></pre> <ul> <li>Loading 20 messages, newer than message with ID <code>MSGID</code>:</li> </ul> <pre><code>messages.getHistory({offset_id: MSGID, add_offset: -20, limit: 20})</code></pre> <ul> <li>Loading 20 messages around message with ID <code>MSGID</code>:</li> </ul> <pre><code>messages.getHistory({offset_id: MSGID, add_offset: -10, limit: 20})</code></pre> <h3><a class="anchor" name="additional-filtering" href="#additional-filtering"><i class="anchor-icon"></i></a>Additional filtering</h3> <p>There is a number of parameters, which are applied to the list after slicing with offset and limit, to reduce the result subset even more:</p> <ul> <li><strong>max_id</strong>: Can be used to only return results with ID strictly smaller than <code>max_id</code> (e.g. message ID)</li> <li><strong>min_id</strong>: Can be used to only return results with ID strictly greater than <code>min_id</code>(e.g. message ID)</li> <li><strong>max_date</strong>: Can be used to only return results that are older than <code>max_date</code>:</li> <li><strong>min_date</strong>: Can be used to only return results with are newer than <code>min_date</code>:</li> <li><strong>hash</strong>: See below.</li> </ul> <h3><a class="anchor" name="hash-generation" href="#hash-generation"><i class="anchor-icon"></i></a>Hash generation</h3> <p>To further reduce the result subset, there is a mechanism to avoid fetching data if the resulting list hasn't changed from the one stored on client, similar to <a href="https://en.wikipedia.org/wiki/HTTP_ETag">ETag</a>.</p> <p>When the client has cached results for API request, it can calculate the <code>hash</code> value for it by taking the result IDs (message IDs or other fields with name <code>id</code>) and using them to compute a 64-bit hash with the following algorithm:</p> <pre><code># Here, ^ indicates a bitwise XOR hash = 0 for id in ids: hash = hash ^ (hash >> 21) hash = hash ^ (hash << 35) hash = hash ^ (hash >> 4) hash = hash + id</code></pre> <p>In some cases, the result container already has a <code>hash</code> field, that can be used instead.</p> <p>When the client passes a correct value, the API will return one of <code>*NotModified</code> constructors, e.g. <a href="/constructor/messages.messagesNotModified">messages.messagesNotModified</a> instead of the actual results.</p> <h3><a class="anchor" name="example-methods" href="#example-methods"><i class="anchor-icon"></i></a>Example methods</h3> <ul> <li><a href="/method/messages.getHistory">messages.getHistory</a> supports all result navigation parameters including message ID hashes and except filters</li> <li><a href="/method/channels.getParticipants">channels.getParticipants</a> supports simple navigation using <strong>limit</strong> and <strong>offset</strong>, along with filtering and <code>hash</code> reducing using the user IDs of returned participants</li> </ul> </div> </div> </div> </div> <div class="footer_wrap"> <div class="footer_columns_wrap footer_desktop"> <div class="footer_column footer_column_telegram"> <h5>Telegram</h5> <div class="footer_telegram_description"></div> Telegram is a cloud-based mobile and desktop messaging app with a focus on security and speed. </div> <div class="footer_column"> <h5><a href="//telegram.org/faq">About</a></h5> <ul> <li><a href="//telegram.org/faq">FAQ</a></li> <li><a href="//telegram.org/privacy">Privacy</a></li> <li><a href="//telegram.org/press">Press</a></li> </ul> </div> <div 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