13 |
14 |
21 |
22 |
23 |
24 |
25 |
26 |
27 |
28 |
29 |
30 |
31 |
32 |
33 |
36 |
37 |
38 |
39 |
--------------------------------------------------------------------------------
/lib/get.js:
--------------------------------------------------------------------------------
1 | var AWS = require('aws-sdk');
2 | AWS.config.region = 'eu-west-1';
3 | var bucket = 'dwyl';
4 | var s3 = new AWS.S3();
5 | var s3bucket = new AWS.S3({params: {Bucket: bucket}});
6 |
7 | var allKeys = [];
8 |
9 | var PARAMS = {
10 | Bucket: bucket,
11 | Delimiter: '',
12 | EncodingType: 'url',
13 | Marker: '0',
14 | Prefix: 'chat/'
15 | }
16 |
17 | function listAllKeys(params, cb) {
18 | // console.log(params);
19 | s3.listObjects(params, function(err, data){
20 | // console.log(err, data.Marker, data.IsTruncated);
21 | // if(!err && data) {
22 | data.Contents.forEach(function(i){
23 | allKeys.push(i)
24 | })
25 | // }
26 | // un-comment this when there are more than 1000 messages in the bank!
27 | // if(data.IsTruncated) {
28 | // var nextParams = JSON.parse(JSON.stringify(params)); // clone params
29 | // nextParams.Marker = allKeys[allKeys.length -1].Key.replace('%3A',':'); // recycle params
30 | // return listAllKeys(nextParams, cb);
31 | // }
32 | // else {
33 | var sorted = allKeys
34 | .filter((e) => {return e.Key.match(/\.json/)})
35 | .sort((a, b) => { return new Date(a.LastModified).getTime() < new Date(b.LastModified).getTime(); });
36 | cb(null, sorted);
37 | // }
38 | });
39 | }
40 |
41 | function get_messages (keys, callback) {
42 | var messages = [];
43 | var count = 0;
44 | keys.forEach((k) => {
45 | s3.getObject({Bucket: bucket, Key: k.Key}, function (err, data){
46 | // console.log(err,data);
47 | // attempt to parse the data as JSON
48 | try {
49 | var json = JSON.parse(data.Body.toString());
50 | messages.push({
51 | m: json.m,
52 | n: json.n,
53 | t: json.t
54 | });
55 | // console.log(messages[messages.length - 1]);
56 | } catch (e) {} // do nothing if it fails.
57 | if(++count === keys.length) {
58 | var sorted = messages.sort((a,b) => {
59 | return new Date(a.t).getTime() > new Date(b.t).getTime();
60 | });
61 | callback(null, sorted);
62 | }
63 | });
64 | });
65 | }
66 |
67 | module.exports = function get_all_messages_in_order (callback) {
68 | allKeys = []; // reset the array! ... TODO: don't use GLOBAL!
69 | listAllKeys(PARAMS, function(err, sorted){
70 | get_messages(sorted, callback);
71 | });
72 | };
73 |
--------------------------------------------------------------------------------
/lib/api_gateway_form_mapping_template.txt:
--------------------------------------------------------------------------------
1 | ## convert HTML POST data or HTTP GET query string to JSON
2 | ## https://forums.aws.amazon.com/thread.jspa?messageID=673012
3 |
4 | ## get the raw post data from the AWS built-in variable and give it a nicer name
5 | #if ($context.httpMethod == "POST")
6 | #set($rawAPIData = $input.path('$'))
7 | #elseif ($context.httpMethod == "GET")
8 | #set($rawAPIData = $input.params().querystring)
9 | #set($rawAPIData = $rawAPIData.toString())
10 | #set($rawAPIDataLength = $rawAPIData.length() - 1)
11 | #set($rawAPIData = $rawAPIData.substring(1, $rawAPIDataLength))
12 | #set($rawAPIData = $rawAPIData.replace(", ", "&"))
13 | #else
14 | #set($rawAPIData = "")
15 | #end
16 |
17 | ## first we get the number of "&" in the string, this tells us if there is more than one key value pair
18 | #set($countAmpersands = $rawAPIData.length() - $rawAPIData.replace("&", "").length())
19 |
20 | ## if there are no "&" at all then we have only one key value pair.
21 | ## we append an ampersand to the string so that we can tokenise it the same way as multiple kv pairs.
22 | ## the "empty" kv pair to the right of the ampersand will be ignored anyway.
23 | #if ($countAmpersands == 0)
24 | #set($rawPostData = $rawAPIData + "&")
25 | #end
26 |
27 | ## now we tokenise using the ampersand(s)
28 | #set($tokenisedAmpersand = $rawAPIData.split("&"))
29 |
30 | ## we set up a variable to hold the valid key value pairs
31 | #set($tokenisedEquals = [])
32 |
33 | ## now we set up a loop to find the valid key value pairs, which must contain only one "="
34 | #foreach( $kvPair in $tokenisedAmpersand )
35 | #set($countEquals = $kvPair.length() - $kvPair.replace("=", "").length())
36 | #if ($countEquals == 1)
37 | #set($kvTokenised = $kvPair.split("="))
38 | #if ($kvTokenised[0].length() > 0)
39 | ## we found a valid key value pair. add it to the list.
40 | #set($devNull = $tokenisedEquals.add($kvPair))
41 | #end
42 | #end
43 | #end
44 |
45 | ## next we set up our loop inside the output structure "{" and "}"
46 | {
47 | "body": {
48 | #foreach( $kvPair in $tokenisedEquals )
49 | ## finally we output the JSON for this pair and append a comma if this isn't the last pair
50 | #set($kvTokenised = $kvPair.split("="))
51 | "$util.urlDecode($kvTokenised[0])" : #if($kvTokenised[1].length() > 0)"$util.urlDecode($kvTokenised[1])"#{else}""#end#if( $foreach.hasNext ),#end
52 | #end
53 | },
54 | ## Now add any other parameters you want to extract
55 | "context" : {
56 | "method" : "$context.httpMethod",
57 | "path" : "$context.resourcePath",
58 | "stage" : "$context.stage",
59 | "source_ip" : "$context.identity.sourceIp",
60 | "user_agent" : "$context.identity.userAgent",
61 | "user_arn" : "$context.identity.userArn",
62 | "request_id" : "$context.requestId",
63 | "resource_id" : "$context.resourceId"
64 | },
65 | "headers": {
66 | #foreach($param in $input.params().header.keySet())
67 | "$param": "$util.escapeJavaScript($input.params().header.get($param))" #if($foreach.hasNext),#end
68 | #end
69 | }
70 | }
71 |
--------------------------------------------------------------------------------
/iot.js:
--------------------------------------------------------------------------------
1 | var data = {
2 | messages: []
3 | };
4 |
5 | new Vue({
6 | el: '#chat',
7 | data: data
8 | });
9 |
10 | document.getElementById('send').addEventListener('click', function (e) {
11 | var say = document.getElementById('say')
12 | send(say.value);
13 | say.value = '';
14 | });
15 |
16 | function SigV4Utils(){}
17 |
18 | SigV4Utils.sign = function(key, msg) {
19 | var hash = CryptoJS.HmacSHA256(msg, key);
20 | return hash.toString(CryptoJS.enc.Hex);
21 | };
22 |
23 | SigV4Utils.sha256 = function(msg) {
24 | var hash = CryptoJS.SHA256(msg);
25 | return hash.toString(CryptoJS.enc.Hex);
26 | };
27 |
28 | SigV4Utils.getSignatureKey = function(key, dateStamp, regionName, serviceName) {
29 | var kDate = CryptoJS.HmacSHA256(dateStamp, 'AWS4' + key);
30 | var kRegion = CryptoJS.HmacSHA256(regionName, kDate);
31 | var kService = CryptoJS.HmacSHA256(serviceName, kRegion);
32 | var kSigning = CryptoJS.HmacSHA256('aws4_request', kService);
33 | return kSigning;
34 | };
35 |
36 | function createEndpoint(regionName, awsIotEndpoint, accessKey, secretKey) {
37 | var time = moment.utc();
38 | var dateStamp = time.format('YYYYMMDD');
39 | var amzdate = dateStamp + 'T' + time.format('HHmmss') + 'Z';
40 | var service = 'iotdevicegateway';
41 | var region = regionName;
42 | var secretKey = secretKey;
43 | var accessKey = accessKey;
44 | var algorithm = 'AWS4-HMAC-SHA256';
45 | var method = 'GET';
46 | var canonicalUri = '/mqtt';
47 | var host = awsIotEndpoint;
48 |
49 | var credentialScope = dateStamp + '/' + region + '/' + service + '/' + 'aws4_request';
50 | var canonicalQuerystring = 'X-Amz-Algorithm=AWS4-HMAC-SHA256';
51 | canonicalQuerystring += '&X-Amz-Credential=' + encodeURIComponent(accessKey + '/' + credentialScope);
52 | canonicalQuerystring += '&X-Amz-Date=' + amzdate;
53 | canonicalQuerystring += '&X-Amz-SignedHeaders=host';
54 |
55 | var canonicalHeaders = 'host:' + host + '\n';
56 | var payloadHash = SigV4Utils.sha256('');
57 | var canonicalRequest = method + '\n' + canonicalUri + '\n' + canonicalQuerystring + '\n' + canonicalHeaders + '\nhost\n' + payloadHash;
58 |
59 | var stringToSign = algorithm + '\n' + amzdate + '\n' + credentialScope + '\n' + SigV4Utils.sha256(canonicalRequest);
60 | var signingKey = SigV4Utils.getSignatureKey(secretKey, dateStamp, region, service);
61 | var signature = SigV4Utils.sign(signingKey, stringToSign);
62 |
63 | canonicalQuerystring += '&X-Amz-Signature=' + signature;
64 | return 'wss://' + host + canonicalUri + '?' + canonicalQuerystring;
65 | }
66 |
67 | var endpoint = createEndpoint(
68 | 'eu-west-1', // Your Region
69 | 'a315z3lphjmasx.iot.eu-west-1.amazonaws.com',
70 | 'AKIAJHXKM73ALW5C4DPA',
71 | 'jykh9E8xVTSp9tNnh+WBrBBrm3XMOTapC4j7zTJ4');
72 | var clientId = Math.random().toString(36).substring(7);
73 | var client = new Paho.MQTT.Client(endpoint, clientId);
74 | var connectOptions = {
75 | useSSL: true,
76 | timeout: 3,
77 | mqttVersion: 4,
78 | onSuccess: subscribe
79 | };
80 | client.connect(connectOptions);
81 | client.onMessageArrived = onMessage;
82 | client.onConnectionLost = function(e) { console.log(e) };
83 |
84 | function subscribe() {
85 | client.subscribe("Test/chat");
86 | console.log("subscribed");
87 | }
88 |
89 | function send(content) {
90 | var message = new Paho.MQTT.Message(content);
91 | message.destinationName = "Test/chat";
92 | client.send(message);
93 | console.log("sent");
94 | }
95 |
96 | function onMessage(message) {
97 | data.messages.push(message.payloadString);
98 | console.log("message received: " + message.payloadString);
99 | }
100 |
--------------------------------------------------------------------------------
/client.js:
--------------------------------------------------------------------------------
1 | var baseURL = 'https://r09u5uw11g.execute-api.eu-west-1.amazonaws.com/prod';
2 |
3 | $( document ).ready(function() {
4 |
5 | function getName() {
6 | // prompt for person's name before allowing to post
7 | var name = Cookies.get('name');
8 | if(!name || name === 'null') {
9 | name = window.prompt("What is your name/handle?");
10 | Cookies.set('name', name);
11 | }
12 | // socket.emit('io:name', name);
13 | $( "#m" ).focus(); // focus cursor on the message input
14 | return name;
15 | }
16 |
17 | function leadZero(number) {
18 | return (number < 10) ? '0'+number : number;
19 | }
20 |
21 | function getTime(timestamp) {
22 | var t, h, m, s, time;
23 | t = new Date(timestamp);
24 | h = leadZero(t.getHours());
25 | m = leadZero(t.getMinutes());
26 | s = leadZero(t.getSeconds());
27 | return '' + h + ':' + m + ':' + s;
28 | }
29 |
30 | function htmlEscape (str) {
31 | return str
32 | .replace(/&/g, "&")
33 | .replace(//g, ">")
35 | .replace(/"/g, """)
36 | .replace(/'/g, "'");
37 | }
38 |
39 | /**
40 | * renders messages to the DOM
41 | * nothing fancy ... where's the React?! Don't Freak out! It works!
42 | */
43 | function renderMessage(msg) {
44 | msg = JSON.parse(msg);
45 | var html = "
";
46 | html += "" + getTime(msg.t) + " ";
47 | html += "" + htmlEscape(msg.n) + ": ";
48 | html += "" + htmlEscape(msg.m) + "";
49 | html += "
";
50 | $('#messages').append(html); // append to list
51 | return;
52 | }
53 |
54 | $('form').submit(function() {
55 |
56 | //if input is empty or white space do not send message
57 | if($('#m').val().match(/^[\s]*$/) !== null) {
58 | $('#m').val('');
59 | $('#m').attr('placeholder', 'please enter your message here');
60 | return false;
61 | }
62 |
63 | if(!Cookies.get('name') || Cookies.get('name').length < 1 || Cookies.get('name') === 'null') {
64 | getName();
65 | return false;
66 | } else {
67 | var msg = $('#m').val();
68 | socket.emit('io:message', msg);
69 | $('#m').val(''); // clear message form ready for next/new message
70 | $('#m').attr('placeholder', ''); //clears placeholder once a msg is successfully sent
71 | return false;
72 | }
73 | });
74 |
75 | // keeps latest message at the bottom of the screen
76 | // http://stackoverflow.com/a/11910887/2870306
77 | function scrollToBottom () {
78 | $(window).scrollTop($('#messages').height());
79 | }
80 |
81 | window.onresize = function(){
82 | scrollToBottom();
83 | }
84 |
85 | // socket.on('chat:messages:latest', function(msg) {
86 | // console.log(">> " +msg);
87 | // renderMessage(msg);
88 | // scrollToBottom();
89 | // });
90 | //
91 | // socket.on('chat:people:new', function(name) {
92 | // $('#joiners').show();
93 | // $('#joined').text(name)
94 | // $('#joiners').fadeOut(5000);
95 | // });
96 |
97 | getName();
98 |
99 | function loadMessages() {
100 | $.get(baseURL + '/chat', function(data){
101 | console.log(data);
102 | data.map(function(msg){
103 | renderMessage(msg);
104 | })
105 | scrollToBottom();
106 | })
107 | }
108 | loadMessages();
109 | });
110 |
111 |
112 |
113 | $(document).ready(function() {
114 |
115 | function getNotes () {
116 |
117 | $.ajax({
118 | type: "GET",
119 | // headers: { 'x-api-key' : API_KEY },
120 | url: baseURL + '/getmessages',
121 | dataType: "json",
122 | success: function(res, status, xhr) {
123 | console.log(' - - - - - - - - getNotes res:')
124 | console.log(res);
125 | $('#notes').val(res.notes)
126 | $('#form').fadeIn('slow'); // this is why I'm using jQuery ... feel free to remove.
127 | },
128 | error: function(xhr, err) {
129 | console.log(' - - - - - - - - xhr:')
130 | console.log(xhr);
131 | console.log(' - - - - - - - - error:')
132 | console.log(err);
133 | }
134 | });
135 | }
136 | getNotes(); // initialise the notes on the page
137 |
138 | // Ajax without JQuery if you prefer:
139 | function postNotes () {
140 | var xhr = new XMLHttpRequest();
141 | xhr.open('POST', baseURL + '/SaveNotes');
142 | xhr.onreadystatechange = function() {
143 | // un-comment these console.logs in for debugging
144 | console.log( xhr.status, xhr.statusText )
145 | console.log(xhr.responseText);
146 | return;
147 | };
148 | var encoded = JSON.stringify({"notes":document.getElementById('notes').value });
149 | xhr.send(encoded);
150 | }
151 |
152 | $( "#send" ).click(function() {
153 | console.log('Save Button Clicked!');
154 | postNotes();
155 | });
156 | });
157 |
--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
1 | # chat
2 |
3 | [](https://travis-ci.org/dwyl/chat)
4 | [](https://codecov.io/gh/dwyl/chat)
5 | [](https://codeclimate.com/github/dwyl/chat)
6 | [](https://david-dm.org/dwyl/chat)
7 | [](https://david-dm.org/dwyl/chat#info=devDependencies)
8 |
9 |
10 | > try it: https://dwyl.s3.amazonaws.com/index.html
11 |
12 | ## Why?
13 |
14 | 
15 |
16 | This repo is designed as a *showcase* for how to build apps that scale.
17 |
18 | We have built chat example apps a couple of times
19 | [*before*](https://github.com/dwyl/hapi-socketio-redis-chat-example)
20 | and the response has been good,
21 | this time our mission is to operate within a *very tight* set of ***constraints***:
22 |
23 | 1. No *Servers*
24 | 2. Progressive Enhancement (_Works when JavaScript is **OFF**_!)
25 | 3. Precisely Predictable (*Linear*) Performance
26 |
27 | ## What?
28 |
29 | Chat. Probably the simplest and easiets to scale implementation you will see ...
30 | unless you work
31 | for `{{ insert name of silicon valley unicorn messenger app here }}`.
32 |
33 | ## How?
34 |
35 | ### Lambda
36 |
37 | https://aws.amazon.com/lambda/
38 | + Request Rate Exceeded:
39 | http://stackoverflow.com/questions/36826352/aws-lambda-toomanyrequestsexception-rate-exceeded/
40 |
41 | ### S3
42 |
43 | We use S3 to render our initial page and host all our static content.
44 | https://aws.amazon.com/s3/
45 | + Node.js SDK Examples: http://docs.aws.amazon.com/AWSJavaScriptSDK/guide/node-examples.html
46 | + Working with Folders: http://docs.aws.amazon.com/AmazonS3/latest/UG/FolderOperations.html
47 |
48 | ### API Gateway
49 |
50 | API Gateway routes the requests we make from the front-end through to
51 | the Lambda function that will process it.
52 |
53 | #### Body Mapping Templates
54 |
55 | In order to allow the data submitted by the client to flow through to the Lambda
56 | we need to define a
57 | ["Body Mapping Template"](http://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-mapping-template-reference.html).
58 |
59 |
60 |
61 | ##### `application/json` Body Mapping Template:
62 | ```js
63 | {
64 | ## extract all params in body as JSON;
65 | "body": $input.json('$'),
66 | "context" : {
67 | "method" : "$context.httpMethod",
68 | "path" : "$context.resourcePath",
69 | "stage" : "$context.stage",
70 | "source_ip" : "$context.identity.sourceIp",
71 | "user_agent" : "$context.identity.userAgent",
72 | "user_arn" : "$context.identity.userArn",
73 | "request_id" : "$context.requestId",
74 | "resource_id" : "$context.resourceId"
75 | },
76 | "headers": {
77 | #foreach($param in $input.params().header.keySet())
78 | "$param": "$util.escapeJavaScript($input.params().header.get($param))" #if($foreach.hasNext),#end
79 | #end
80 | }
81 | }
82 | ```
83 |
84 | Once Body Mapping Template is enabled, test using `curl`:
85 | ```sh
86 | curl -v -H "Content-Type: application/json" -X POST -d '{"m":"Hello World!","n":"yourname","t":"123456"}' https://r09u5uw11g.execute-api.eu-west-1.amazonaws.com/prod/savemessage
87 | ```
88 |
89 | With Authorization Header:
90 | ```sh
91 | curl -v -H "Content-Type: application/json" -X POST -d '{"m":"1348","n":"yourname","t":"12345678"}' -H "Authorization: eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpZCI6MSwibmFtZSI6IkFudGhvbnkgVmFsaWQgVXNlciIsImlhdCI6MTQyNTQ3MzUzNX0.KA68l60mjiC8EXaC2odnjFwdIDxE__iDu5RwLdN1F2A" https://r09u5uw11g.execute-api.eu-west-1.amazonaws.com/prod/savemessage
92 | ```
93 |
94 | GET messages:
95 | ```js
96 | curl https://r09u5uw11g.execute-api.eu-west-1.amazonaws.com/prod/chat
97 | ```
98 |
99 | curl -v -H "Content-Type: application/json" -X POST -d '{"m":"Hello World!","n":"yourname","t":"123456"}' https://r09u5uw11g.execute-api.eu-west-1.amazonaws.com/prod/chat
100 |
101 | + Overview: https://aws.amazon.com/api-gateway/
102 | + SDK Docs: http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/APIGateway.html
103 | + HTTP Method: http://stackoverflow.com/questions/35252544/how-to-get-the-http-method-in-aws-lambda
104 | + Passing form data through API Gateway to Lambda:
105 | http://stackoverflow.com/questions/32057053/how-to-pass-a-params-from-post-to-aws-lambda-from-amazon-api-gateway
106 | which lead to: https://forums.aws.amazon.com/thread.jspa?messageID=673012
107 | + Headers: http://stackoverflow.com/questions/31372167/how-to-access-http-headers-for-request-to-aws-api-gateway-using-lambda
108 | + Velocity Template Language (for mapping):
109 | http://velocity.apache.org/engine/devel/vtl-reference-guide.html
110 | + `Could not parse request body into json` ...
111 | https://forums.aws.amazon.com/thread.jspa?threadID=221749
112 |
113 |
114 |
115 | ### IOT
116 |
117 | ### WebRTC?
118 |
119 | Over **50% of browsers** (Firefox & Chrome) which means
120 | we can cut-out paying for IOT messages for the people
121 | who are using good browsers.
122 |
123 | http://caniuse.com/#feat=rtcpeerconnection
124 |
125 | This also means when we use Electron
126 |
127 | ## How *much* ($£€) ?
128 |
129 | How much does all of this cost...?
130 |
131 | Let's break down the cost in the order of the Tech Stack.
132 |
133 | ### S3
134 |
135 | https://aws.amazon.com/s3/pricing/
136 |
137 | ### API Gateway
138 |
139 | https://aws.amazon.com/api-gateway/pricing/
140 |
141 | > What is a read/write capacity unit?
142 | http://aws.amazon.com/dynamodb/faqs/#What_is_a_readwrite_capacity_unit
143 |
144 | ### Lambda
145 |
146 | https://aws.amazon.com/lambda/pricing/
147 |
148 | ### DynamoDB
149 |
150 | https://aws.amazon.com/dynamodb/pricing/
151 |
152 | ### Cognito
153 |
154 | Amazon Cognito costs $0.15 for each 10,000 sync operations and $0.15 per GB of sync store per month.
155 |
156 | https://aws.amazon.com/cognito/pricing/
157 |
158 | ### IOT
159 |
160 | $5 per million messages.
161 |
162 | A message is a 512-byte block of data processed by AWS IoT – either published to or delivered by the Service. For example, a 900-byte payload is billed as two messages.
163 |
164 | https://aws.amazon.com/iot/pricing/
165 |
166 |
167 |
168 | ## Background Reading
169 |
170 | ### Learning by Doing
171 |
172 | + Access HTTP Headers:
173 | http://stackoverflow.com/questions/31372167/how-to-access-http-headers-for-request-to-aws-api-gateway-using-lambda
174 | + Cookies on Lambda:
175 | http://stackoverflow.com/questions/31851860/access-http-request-headers-query-string-cookies-body-object-in-lambda-with
176 | + Invoke Lambda by HTTP Request:
177 | http://stackoverflow.com/questions/29877220/invoke-a-aws-lambda-function-by-a-http-request
178 | + Render HTML in Lambda:
179 | http://kennbrodhagen.net/2016/01/31/how-to-return-html-from-aws-api-gateway-lambda/
180 | + Render React on Lambda:
181 | https://medium.com/@devknoll/rendering-react-with-amazon-lambda-e4e85a788257
182 |
183 | ### Discussion
184 |
185 | We considered using S3 as our primary data store, but soon realized its not that "*simple*"...
186 | see: Why does S3 still not support Appending? https://news.ycombinator.com/item?id=10746969
187 |
--------------------------------------------------------------------------------
/LICENSE:
--------------------------------------------------------------------------------
1 | GNU GENERAL PUBLIC LICENSE
2 | Version 2, June 1991
3 |
4 | Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
5 | 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
6 | Everyone is permitted to copy and distribute verbatim copies
7 | of this license document, but changing it is not allowed.
8 |
9 | Preamble
10 |
11 | The licenses for most software are designed to take away your
12 | freedom to share and change it. By contrast, the GNU General Public
13 | License is intended to guarantee your freedom to share and change free
14 | software--to make sure the software is free for all its users. This
15 | General Public License applies to most of the Free Software
16 | Foundation's software and to any other program whose authors commit to
17 | using it. (Some other Free Software Foundation software is covered by
18 | the GNU Lesser General Public License instead.) You can apply it to
19 | your programs, too.
20 |
21 | When we speak of free software, we are referring to freedom, not
22 | price. Our General Public Licenses are designed to make sure that you
23 | have the freedom to distribute copies of free software (and charge for
24 | this service if you wish), that you receive source code or can get it
25 | if you want it, that you can change the software or use pieces of it
26 | in new free programs; and that you know you can do these things.
27 |
28 | To protect your rights, we need to make restrictions that forbid
29 | anyone to deny you these rights or to ask you to surrender the rights.
30 | These restrictions translate to certain responsibilities for you if you
31 | distribute copies of the software, or if you modify it.
32 |
33 | For example, if you distribute copies of such a program, whether
34 | gratis or for a fee, you must give the recipients all the rights that
35 | you have. You must make sure that they, too, receive or can get the
36 | source code. And you must show them these terms so they know their
37 | rights.
38 |
39 | We protect your rights with two steps: (1) copyright the software, and
40 | (2) offer you this license which gives you legal permission to copy,
41 | distribute and/or modify the software.
42 |
43 | Also, for each author's protection and ours, we want to make certain
44 | that everyone understands that there is no warranty for this free
45 | software. If the software is modified by someone else and passed on, we
46 | want its recipients to know that what they have is not the original, so
47 | that any problems introduced by others will not reflect on the original
48 | authors' reputations.
49 |
50 | Finally, any free program is threatened constantly by software
51 | patents. We wish to avoid the danger that redistributors of a free
52 | program will individually obtain patent licenses, in effect making the
53 | program proprietary. To prevent this, we have made it clear that any
54 | patent must be licensed for everyone's free use or not licensed at all.
55 |
56 | The precise terms and conditions for copying, distribution and
57 | modification follow.
58 |
59 | GNU GENERAL PUBLIC LICENSE
60 | TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
61 |
62 | 0. This License applies to any program or other work which contains
63 | a notice placed by the copyright holder saying it may be distributed
64 | under the terms of this General Public License. The "Program", below,
65 | refers to any such program or work, and a "work based on the Program"
66 | means either the Program or any derivative work under copyright law:
67 | that is to say, a work containing the Program or a portion of it,
68 | either verbatim or with modifications and/or translated into another
69 | language. (Hereinafter, translation is included without limitation in
70 | the term "modification".) Each licensee is addressed as "you".
71 |
72 | Activities other than copying, distribution and modification are not
73 | covered by this License; they are outside its scope. The act of
74 | running the Program is not restricted, and the output from the Program
75 | is covered only if its contents constitute a work based on the
76 | Program (independent of having been made by running the Program).
77 | Whether that is true depends on what the Program does.
78 |
79 | 1. You may copy and distribute verbatim copies of the Program's
80 | source code as you receive it, in any medium, provided that you
81 | conspicuously and appropriately publish on each copy an appropriate
82 | copyright notice and disclaimer of warranty; keep intact all the
83 | notices that refer to this License and to the absence of any warranty;
84 | and give any other recipients of the Program a copy of this License
85 | along with the Program.
86 |
87 | You may charge a fee for the physical act of transferring a copy, and
88 | you may at your option offer warranty protection in exchange for a fee.
89 |
90 | 2. You may modify your copy or copies of the Program or any portion
91 | of it, thus forming a work based on the Program, and copy and
92 | distribute such modifications or work under the terms of Section 1
93 | above, provided that you also meet all of these conditions:
94 |
95 | a) You must cause the modified files to carry prominent notices
96 | stating that you changed the files and the date of any change.
97 |
98 | b) You must cause any work that you distribute or publish, that in
99 | whole or in part contains or is derived from the Program or any
100 | part thereof, to be licensed as a whole at no charge to all third
101 | parties under the terms of this License.
102 |
103 | c) If the modified program normally reads commands interactively
104 | when run, you must cause it, when started running for such
105 | interactive use in the most ordinary way, to print or display an
106 | announcement including an appropriate copyright notice and a
107 | notice that there is no warranty (or else, saying that you provide
108 | a warranty) and that users may redistribute the program under
109 | these conditions, and telling the user how to view a copy of this
110 | License. (Exception: if the Program itself is interactive but
111 | does not normally print such an announcement, your work based on
112 | the Program is not required to print an announcement.)
113 |
114 | These requirements apply to the modified work as a whole. If
115 | identifiable sections of that work are not derived from the Program,
116 | and can be reasonably considered independent and separate works in
117 | themselves, then this License, and its terms, do not apply to those
118 | sections when you distribute them as separate works. But when you
119 | distribute the same sections as part of a whole which is a work based
120 | on the Program, the distribution of the whole must be on the terms of
121 | this License, whose permissions for other licensees extend to the
122 | entire whole, and thus to each and every part regardless of who wrote it.
123 |
124 | Thus, it is not the intent of this section to claim rights or contest
125 | your rights to work written entirely by you; rather, the intent is to
126 | exercise the right to control the distribution of derivative or
127 | collective works based on the Program.
128 |
129 | In addition, mere aggregation of another work not based on the Program
130 | with the Program (or with a work based on the Program) on a volume of
131 | a storage or distribution medium does not bring the other work under
132 | the scope of this License.
133 |
134 | 3. You may copy and distribute the Program (or a work based on it,
135 | under Section 2) in object code or executable form under the terms of
136 | Sections 1 and 2 above provided that you also do one of the following:
137 |
138 | a) Accompany it with the complete corresponding machine-readable
139 | source code, which must be distributed under the terms of Sections
140 | 1 and 2 above on a medium customarily used for software interchange; or,
141 |
142 | b) Accompany it with a written offer, valid for at least three
143 | years, to give any third party, for a charge no more than your
144 | cost of physically performing source distribution, a complete
145 | machine-readable copy of the corresponding source code, to be
146 | distributed under the terms of Sections 1 and 2 above on a medium
147 | customarily used for software interchange; or,
148 |
149 | c) Accompany it with the information you received as to the offer
150 | to distribute corresponding source code. (This alternative is
151 | allowed only for noncommercial distribution and only if you
152 | received the program in object code or executable form with such
153 | an offer, in accord with Subsection b above.)
154 |
155 | The source code for a work means the preferred form of the work for
156 | making modifications to it. For an executable work, complete source
157 | code means all the source code for all modules it contains, plus any
158 | associated interface definition files, plus the scripts used to
159 | control compilation and installation of the executable. However, as a
160 | special exception, the source code distributed need not include
161 | anything that is normally distributed (in either source or binary
162 | form) with the major components (compiler, kernel, and so on) of the
163 | operating system on which the executable runs, unless that component
164 | itself accompanies the executable.
165 |
166 | If distribution of executable or object code is made by offering
167 | access to copy from a designated place, then offering equivalent
168 | access to copy the source code from the same place counts as
169 | distribution of the source code, even though third parties are not
170 | compelled to copy the source along with the object code.
171 |
172 | 4. You may not copy, modify, sublicense, or distribute the Program
173 | except as expressly provided under this License. Any attempt
174 | otherwise to copy, modify, sublicense or distribute the Program is
175 | void, and will automatically terminate your rights under this License.
176 | However, parties who have received copies, or rights, from you under
177 | this License will not have their licenses terminated so long as such
178 | parties remain in full compliance.
179 |
180 | 5. You are not required to accept this License, since you have not
181 | signed it. However, nothing else grants you permission to modify or
182 | distribute the Program or its derivative works. These actions are
183 | prohibited by law if you do not accept this License. Therefore, by
184 | modifying or distributing the Program (or any work based on the
185 | Program), you indicate your acceptance of this License to do so, and
186 | all its terms and conditions for copying, distributing or modifying
187 | the Program or works based on it.
188 |
189 | 6. Each time you redistribute the Program (or any work based on the
190 | Program), the recipient automatically receives a license from the
191 | original licensor to copy, distribute or modify the Program subject to
192 | these terms and conditions. You may not impose any further
193 | restrictions on the recipients' exercise of the rights granted herein.
194 | You are not responsible for enforcing compliance by third parties to
195 | this License.
196 |
197 | 7. If, as a consequence of a court judgment or allegation of patent
198 | infringement or for any other reason (not limited to patent issues),
199 | conditions are imposed on you (whether by court order, agreement or
200 | otherwise) that contradict the conditions of this License, they do not
201 | excuse you from the conditions of this License. If you cannot
202 | distribute so as to satisfy simultaneously your obligations under this
203 | License and any other pertinent obligations, then as a consequence you
204 | may not distribute the Program at all. For example, if a patent
205 | license would not permit royalty-free redistribution of the Program by
206 | all those who receive copies directly or indirectly through you, then
207 | the only way you could satisfy both it and this License would be to
208 | refrain entirely from distribution of the Program.
209 |
210 | If any portion of this section is held invalid or unenforceable under
211 | any particular circumstance, the balance of the section is intended to
212 | apply and the section as a whole is intended to apply in other
213 | circumstances.
214 |
215 | It is not the purpose of this section to induce you to infringe any
216 | patents or other property right claims or to contest validity of any
217 | such claims; this section has the sole purpose of protecting the
218 | integrity of the free software distribution system, which is
219 | implemented by public license practices. Many people have made
220 | generous contributions to the wide range of software distributed
221 | through that system in reliance on consistent application of that
222 | system; it is up to the author/donor to decide if he or she is willing
223 | to distribute software through any other system and a licensee cannot
224 | impose that choice.
225 |
226 | This section is intended to make thoroughly clear what is believed to
227 | be a consequence of the rest of this License.
228 |
229 | 8. If the distribution and/or use of the Program is restricted in
230 | certain countries either by patents or by copyrighted interfaces, the
231 | original copyright holder who places the Program under this License
232 | may add an explicit geographical distribution limitation excluding
233 | those countries, so that distribution is permitted only in or among
234 | countries not thus excluded. In such case, this License incorporates
235 | the limitation as if written in the body of this License.
236 |
237 | 9. The Free Software Foundation may publish revised and/or new versions
238 | of the General Public License from time to time. Such new versions will
239 | be similar in spirit to the present version, but may differ in detail to
240 | address new problems or concerns.
241 |
242 | Each version is given a distinguishing version number. If the Program
243 | specifies a version number of this License which applies to it and "any
244 | later version", you have the option of following the terms and conditions
245 | either of that version or of any later version published by the Free
246 | Software Foundation. If the Program does not specify a version number of
247 | this License, you may choose any version ever published by the Free Software
248 | Foundation.
249 |
250 | 10. If you wish to incorporate parts of the Program into other free
251 | programs whose distribution conditions are different, write to the author
252 | to ask for permission. For software which is copyrighted by the Free
253 | Software Foundation, write to the Free Software Foundation; we sometimes
254 | make exceptions for this. Our decision will be guided by the two goals
255 | of preserving the free status of all derivatives of our free software and
256 | of promoting the sharing and reuse of software generally.
257 |
258 | NO WARRANTY
259 |
260 | 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
261 | FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
262 | OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
263 | PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
264 | OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
265 | MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS
266 | TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
267 | PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
268 | REPAIR OR CORRECTION.
269 |
270 | 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
271 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
272 | REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
273 | INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
274 | OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
275 | TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
276 | YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
277 | PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
278 | POSSIBILITY OF SUCH DAMAGES.
279 |
280 | END OF TERMS AND CONDITIONS
281 |
282 | How to Apply These Terms to Your New Programs
283 |
284 | If you develop a new program, and you want it to be of the greatest
285 | possible use to the public, the best way to achieve this is to make it
286 | free software which everyone can redistribute and change under these terms.
287 |
288 | To do so, attach the following notices to the program. It is safest
289 | to attach them to the start of each source file to most effectively
290 | convey the exclusion of warranty; and each file should have at least
291 | the "copyright" line and a pointer to where the full notice is found.
292 |
293 | {description}
294 | Copyright (C) {year} {fullname}
295 |
296 | This program is free software; you can redistribute it and/or modify
297 | it under the terms of the GNU General Public License as published by
298 | the Free Software Foundation; either version 2 of the License, or
299 | (at your option) any later version.
300 |
301 | This program is distributed in the hope that it will be useful,
302 | but WITHOUT ANY WARRANTY; without even the implied warranty of
303 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
304 | GNU General Public License for more details.
305 |
306 | You should have received a copy of the GNU General Public License along
307 | with this program; if not, write to the Free Software Foundation, Inc.,
308 | 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
309 |
310 | Also add information on how to contact you by electronic and paper mail.
311 |
312 | If the program is interactive, make it output a short notice like this
313 | when it starts in an interactive mode:
314 |
315 | Gnomovision version 69, Copyright (C) year name of author
316 | Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
317 | This is free software, and you are welcome to redistribute it
318 | under certain conditions; type `show c' for details.
319 |
320 | The hypothetical commands `show w' and `show c' should show the appropriate
321 | parts of the General Public License. Of course, the commands you use may
322 | be called something other than `show w' and `show c'; they could even be
323 | mouse-clicks or menu items--whatever suits your program.
324 |
325 | You should also get your employer (if you work as a programmer) or your
326 | school, if any, to sign a "copyright disclaimer" for the program, if
327 | necessary. Here is a sample; alter the names:
328 |
329 | Yoyodyne, Inc., hereby disclaims all copyright interest in the program
330 | `Gnomovision' (which makes passes at compilers) written by James Hacker.
331 |
332 | {signature of Ty Coon}, 1 April 1989
333 | Ty Coon, President of Vice
334 |
335 | This General Public License does not permit incorporating your program into
336 | proprietary programs. If your program is a subroutine library, you may
337 | consider it more useful to permit linking proprietary applications with the
338 | library. If this is what you want to do, use the GNU Lesser General
339 | Public License instead of this License.
340 |
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