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/* Copyright (c) 2012: Daniel Richman. License: GNU GPL 3 */
/* Additional features: Priyesh Patel */
(function () {
var dataelem = "#data";
var pausetoggle = "#pause";
var scrollelems = ["html", "body"];
var url = "ceph-watch.log";
var fix_rn = true;
var load = 10 * 1024; /* 10KB */
var poll = 1000; /* 1s */
var kill = false;
var loading = false;
var pause = false;
var reverse = true;
var log_data = "";
var log_file_size = 0;
/* :-( https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt */
function parseInt2(value) {
if(!(/^[0-9]+$/.test(value))) throw "Invalid integer " + value;
var v = Number(value);
if (isNaN(v)) throw "Invalid integer " + value;
return v;
}
function get_log() {
if (kill | loading) return;
loading = true;
var range;
var first_load;
var must_get_206;
if (log_file_size === 0) {
/* Get the last 'load' bytes */
range = "-" + load.toString();
first_load = true;
must_get_206 = false;
} else {
/* Get the (log_file_size - 1)th byte, onwards. */
range = (log_file_size - 1).toString() + "-";
first_load = false;
must_get_206 = log_file_size > 1;
}
/* The "log_file_size - 1" deliberately reloads the last byte, which we already
* have. This is to prevent a 416 "Range unsatisfiable" error: a response
* of length 1 tells us that the file hasn't changed yet. A 416 shows that
* the file has been trucnated */
$.ajax(url, {
dataType: "text",
cache: false,
headers: {Range: "bytes=" + range},
success: function (data, s, xhr) {
loading = false;
var content_size;
if (xhr.status === 206) {
var c_r = xhr.getResponseHeader("Content-Range");
if (!c_r)
throw "Server did not respond with a Content-Range";
log_file_size = parseInt2(c_r.split("/")[1]);
content_size = parseInt2(xhr.getResponseHeader("Content-Length"));
} else if (xhr.status === 200) {
if (must_get_206)
throw "Expected 206 Partial Content";
content_size = log_file_size =
parseInt2(xhr.getResponseHeader("Content-Length"));
} else {
throw "Unexpected status " + xhr.status;
}
if (first_load && data.length > load)
throw "Server's response was too long";
var added = false;
if (first_load) {
/* Clip leading part-line if not the whole file */
if (content_size < log_file_size) {
var start = data.indexOf("\n");
log_data = data.substring(start + 1);
} else {
log_data = data;
}
added = true;
} else {
/* Drop the first byte (see above) */
log_data += data.substring(1);
if (log_data.length > load) {
var start = log_data.indexOf("\n", log_data.length - load);
log_data = log_data.substring(start + 1);
}
if (data.length > 1)
added = true;
}
if (added)
show_log(added);
setTimeout(get_log, poll);
},
error: function (xhr, s, t) {
loading = false;
if (xhr.status === 416 || xhr.status == 404) {
/* 416: Requested range not satisfiable: log was truncated. */
/* 404: Retry soon, I guess */
log_file_size = 0;
log_data = "";
show_log();
setTimeout(get_log, poll);
} else {
throw "Unknown AJAX Error (status " + xhr.status + ")";
}
}
});
}
function scroll(where) {
for (var i = 0; i < scrollelems.length; i++) {
var s = $(scrollelems[i]);
if (where === -1)
s.scrollTop(s.height());
else
s.scrollTop(where);
}
}
function show_log() {
if (pause) return;
var t = log_data;
if (reverse) {
var t_a = t.split(/\n/g);
t_a.reverse();
if (t_a[0] == "")
t_a.shift();
t = t_a.join("\n");
}
if (fix_rn)
t = t.replace(/\n/g, "\r\n");
$(dataelem).text(t);
if (!reverse)
scroll(-1);
}
function error(what) {
kill = true;
$(dataelem).text("An error occured :-(.\r\n" +
"Reloading may help; no promises.\r\n" +
what);
scroll(0);
return false;
}
$(document).ready(function () {
window.onerror = error;
/* If URL is /logtail/?noreverse display in chronological order */
var hash = location.search.replace(/^\?/, "");
if (hash == "noreverse")
reverse = false;
/* Add pause toggle */
$(pausetoggle).click(function (e) {
pause = !pause;
$(pausetoggle).text(pause ? "Unpause" : "Pause");
show_log();
e.preventDefault();
});
get_log();
});
})();
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