|
| 1 | +(function () { |
| 2 | + |
| 3 | +var dataelem = "#data"; |
| 4 | +var scrollelem = "body"; |
| 5 | + |
| 6 | +var url = "log"; |
| 7 | +var load = 10024; /* 10KB */ |
| 8 | +var poll = 1000; /* 1s */ |
| 9 | + |
| 10 | +var kill = false; |
| 11 | +var loading = false; |
| 12 | +var log_data = null; |
| 13 | +var log_size = null; |
| 14 | + |
| 15 | +function get_log() { |
| 16 | + if (kill | loading) return; |
| 17 | + loading = true; |
| 18 | + |
| 19 | + var range; |
| 20 | + if (log_size === null) |
| 21 | + /* Get the last 'load' bytes */ |
| 22 | + range = "-" + load.toString(); |
| 23 | + else |
| 24 | + /* Get the (log_size - 1)th byte, onwards. */ |
| 25 | + range = (log_size - 1).toString() + "-"; |
| 26 | + |
| 27 | + /* The "log_size - 1" deliberately reloads the last byte, which we already |
| 28 | + * have. This is to prevent a 416 "Range unsatisfiable" error: a response |
| 29 | + * of length 1 tells us that the file hasn't changed yet. A 416 shows that |
| 30 | + * the file has been trucnated */ |
| 31 | + |
| 32 | + $.ajax(url, { |
| 33 | + cache: false, |
| 34 | + headers: {Range: "bytes=" + range}, |
| 35 | + success: function (data, s, xhr) { |
| 36 | + loading = false; |
| 37 | + |
| 38 | + if (xhr.status !== 206) /* Partial Content */ |
| 39 | + throw "Server did not respond 206"; |
| 40 | + var c_r = xhr.getResponseHeader("Content-Range"); |
| 41 | + if (c_r === null) |
| 42 | + throw "Server did not respond with a Content-Range"; |
| 43 | + |
| 44 | + log_size = parseInt(c_r.split("/")[1]); |
| 45 | + if (isNaN(log_size)) |
| 46 | + throw "Invalid Content-Range size"; |
| 47 | + |
| 48 | + var added = false; |
| 49 | + |
| 50 | + if (log_data === null) { |
| 51 | + /* Clip leading part-line if not the whole file */ |
| 52 | + if (data.length !== log_size) { |
| 53 | + var start = data.indexOf("\n"); |
| 54 | + log_data = data.substring(start + 1); |
| 55 | + } else { |
| 56 | + log_data = data; |
| 57 | + } |
| 58 | + |
| 59 | + added = true; |
| 60 | + } else { |
| 61 | + /* Drop the first byte (see above) */ |
| 62 | + log_data += data.substring(1); |
| 63 | + |
| 64 | + if (log_data.length > load) { |
| 65 | + var start = log_data.indexOf("\n", log_data.length - load); |
| 66 | + log_data = log_data.substring(start + 1); |
| 67 | + } |
| 68 | + |
| 69 | + if (data.length > 1) |
| 70 | + added = true; |
| 71 | + } |
| 72 | + |
| 73 | + show_log(added); |
| 74 | + setTimeout(get_log, poll); |
| 75 | + }, |
| 76 | + error: function (xhr, s, t) { |
| 77 | + loading = false; |
| 78 | + |
| 79 | + if (xhr.status === 416 || xhr.status == 404) { |
| 80 | + /* 416: Requested range not satisfiable: log was truncated. */ |
| 81 | + /* 404: Retry soon, I guess */ |
| 82 | + |
| 83 | + log_size = null; |
| 84 | + log_data = null; |
| 85 | + show_log(true); |
| 86 | + |
| 87 | + setTimeout(get_log, poll); |
| 88 | + } else { |
| 89 | + if (s == "error") |
| 90 | + error(xhr.statusText); |
| 91 | + else |
| 92 | + error("AJAX Error: " + s); |
| 93 | + } |
| 94 | + } |
| 95 | + }); |
| 96 | +} |
| 97 | + |
| 98 | +function show_log(scroll) { |
| 99 | + var d = $(dataelem); |
| 100 | + var s = $(scrollelem); |
| 101 | + |
| 102 | + if (log_data !== null) |
| 103 | + d.text(log_data); |
| 104 | + else |
| 105 | + d.text(""); |
| 106 | + |
| 107 | + if (scroll) |
| 108 | + s.scrollTop(s.height()); |
| 109 | +} |
| 110 | + |
| 111 | +function error(what) { |
| 112 | + kill = true; |
| 113 | + /* TODO: error msg */ |
| 114 | +} |
| 115 | + |
| 116 | +$(document).ready(function () { |
| 117 | + $(window).error(error); |
| 118 | + get_log(); |
| 119 | +}); |
| 120 | + |
| 121 | +})(); |
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