functioning rest-style chart server!

views/chart.php

@@ -0,0 +1,89 @@
+<?php
+use phpFastCache\CacheManager;
+
+function getJson($url) {
+  if (empty($url)) {
+    trigger_error('Missing or empty JSON url');
+  }
+  $ch = curl_init($url);
+  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
+  curl_setopt($ch, CURLOPT_HTTPHEADER, array('Accept: application/json'));
+  curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 30);
+  curl_setopt($ch, CURLOPT_TIMEOUT, 30);
+  // http://unitstep.net/blog/2009/05/05/using-curl-in-php-to-access-https-ssltls-protected-sites/
+//  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
+//  curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
+//  curl_setopt($ch, CURLOPT_CAINFO, getcwd() . "/VeriSignClass3PublicPrimaryCertificationAuthority-G5.pem");
+
+  $result = curl_exec($ch);
+  $result = json_decode($result) or trigger_error('Couldn\'t parse JSON');
+  return $result;
+}
+
+function renderChart(
+  $pair,
+  $dataDuration = (7 * 24 * 60 * 60),
+  $dataResolution = 1800,
+  $format = 'svg',
+  $color = '#000',
+  $width = 800,
+  $height = 200,
+  $fontSize = 12
+) {
+
+  $result = CacheManager::get('poloniex-'.$pair.'-'.$dataDuration.'-'.$format);
+
+  if (is_null($result)) {
+    $startTime = time() - $dataDuration;
+    $poloniexUrl = 'https://poloniex.com/public?command=returnChartData&currencyPair=' . $pair . '&start=' . $startTime . '&end=9999999999&period=' . $dataResolution;
+
+    $poloniexJson = CacheManager::get('poloniex-json-'.$pair.'-'.$dataDuration);
+
+    if(is_null($poloniexJson)) {
+      $poloniexJson = getJson($poloniexUrl);
+      // Write to cache for next time
+      CacheManager::set('poloniex-json-'.$pair.'-'.$dataDuration, $poloniexJson, $dataDuration);
+    }
+
+    $chartData = [];
+
+    foreach ($poloniexJson as $item) {
+      $chartData[$item->date] = $item->weightedAverage;
+    }
+
+    $poloniexChart = new NeatCharts\LineChart($chartData, [
+      'width'=>800,
+      'height'=>200,
+      'lineColor'=>"#1C75BC", // Dash blue
+      'labelColor'=>"#000",
+      'smoothed'=>false,
+      'fontSize'=>12
+    ]);
+    $result = $poloniexChart->render();
+
+    if ($format == 'png') {
+      $im = new Imagick();
+      $im->setBackgroundColor(new ImagickPixel("transparent"));
+      $im->readImageBlob($result);
+      $im->setImageFormat("png32");
+      $result = $im->getImageBlob();
+      $im->clear();
+      $im->destroy();
+    }
+    CacheManager::set('poloniex-'.$pair.'-'.$dataDuration.'-'.$format, $result, $dataDuration);
+    $resultExpires = time() + $dataDuration;
+  } else {
+    $resultExpires = CacheManager::getInfo('poloniex-'.$pair.'-'.$dataDuration.'-'.$format)[ 'expired_time' ];
+    $startTime = $resultExpires - $dataDuration;
+  }
+
+  header('Expires: '.gmdate("D, d M Y H:i:s", $resultExpires));
+  if ($format == 'svg') {
+    header('Content-type: image/svg+xml; charset=utf-8');
+    header('Content-Disposition: inline; filename="Dash-chart-' . gmdate('Y-m-d\THis+0', $startTime) . '--' . gmdate('Y-m-d\THis+0') . '.svg"');
+  } else if ($format == 'png') {
+    header("Content-Type: image/png");
+    header('Content-Disposition: inline; filename="Dash-chart-' . gmdate('Y-m-d\THis+0', $startTime) . '--' . gmdate('Y-m-d\THis+0') . '.png"');
+  }
+  echo $result;
+}

views/fakeStockData.php

@@ -0,0 +1,23 @@
+<?php
+
+$chartData = [];
+
+$offset = 100 * (rand()/getRandMax())**4;
+$scale = 100 * (rand()/getRandMax())**2;
+$volatility = 0.5 * (rand()/getRandMax())**3;
+
+for ($n = 0, $current = $offset + 0.5 * $scale; $n < 96; $n++) {
+  $current -= $offset;
+  $current *= 1 + $volatility * (rand()/getRandMax() - 0.5);
+  $current += $offset;
+  $chartData[$n] = $current;
+}
+
+$stockChart = new NeatCharts\LineChart($chartData, [
+  "width"=>500,
+  "height"=>150,
+  "fontSize"=>10
+]);
+print $stockChart->render();
+
+?>

views/fakeTempData.php

@@ -0,0 +1,24 @@
+<?php
+$chartData = [];
+
+$start = 100 * (rand()/getRandMax())**3;
+$volatility = rand()/getRandMax() + 0.01;
+$velocity = (rand()/getRandMax() - 0.5);
+$acceleration = 0.1 * (rand()/getRandMax())**2;
+
+for ($n = 0, $current = $start; $n < 12; $n++) {
+  $velocity *= 0.5;
+  $velocity += $acceleration * 2 * (rand()/getRandMax() - 0.5);
+  $current += $velocity;
+  $chartData[$n] = $current;
+}
+
+$tempChart = new NeatCharts\LineChart($chartData,  [
+  "width"=>700,
+  "height"=>400,
+  "lineColor"=>"#D00",
+  "labelColor"=>"#777",
+  "smoothed"=>true
+]);
+print $tempChart->render();
+?>

views/index.php

@@ -0,0 +1,43 @@
+<!DOCTYPE html>
+<html lang="en-US">
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, minimum-scale=1.0, maximum-scale=1.0">
+  <title>NeatCharts demo</title>
+  <style>
+    main {
+      -webkit-columns: 800px 2;
+      -moz-columns: 800px 2;
+      columns: 800px 2;
+    }
+    section {
+      display: inline-block;
+      width: auto;
+      max-width: 800px;
+      padding: 10px;
+      vertical-align: top;
+    }
+  </style>
+</head>
+
+<body>
+  <header>
+    <h1>NeatCharts demo</h1>
+  </header>
+  <main>
+    <section>
+      <h2>Poloniex Dash/BTC Price</h2>
+      <img src="/charts/dash/24h" alt="Poloniex Dash/BTC price">
+    </section>
+
+    <section>
+      <h2>Fake Stock Market Data</h2>
+    </section>
+
+    <section>
+      <h2>Monotonically Smoothed Chart</h2>
+    </section>
+  </main>
+
+</body>
+</html>