Rapid API development examples for Impress Application Server / Node.js (jsfwdays 2014)

Rapid API development examples for
Impress Application Server (Node.js)
Timur Shemsedinov
Research Institute of System Technologies (UA, Kiev), MetaSystems Inc.
mailto:timur.shemsedinov@gmail.com https://github.com/tshemsedinov/impress
http://habrahabr.ru/users/marcusaurelius/ https://www.npmjs.org/package/impress

Impress Application Server is:
• Scaling transparent to applications
• Application isolation (memory configuration database)
• Deployment or update code without restart
• Highload serving static files from memory (gzip, js minification, etc.)
• URL-rewriting using RegExp, with internal redirection or sending
external HTTP-requests (reverse proxying)
• Virtual hosts with multi-domain support (e.g.: *.domain.com)
• Executable code and static caching in RAM
• TCP port multiplexing and demultiplexing between applications
• Server-Sent Events and WebSocket support
• Stateless API (REST) and stateful API (RPC) support with IP-sticky
and Cookie-sticky to associated processes and global state sync.
• Many other features: sessions, rotating logging, IPC and ZeroMQ,
database access drivers, etc.

Rapid API development examples
General principles:
• Request routing based on file system
• Each handler in separate file, handler inherit/override mechanism
• Handlers need not prepare request execution environment, such as
import/load libraries, establish db connections, build memory
structures, etc., request will come to ready application environment
and handler will contain just applied code
• Each application have own isolated context and in-memory state
• Long and batch workers in separate threads (forking by Impress
Application Server into parallel processes)
• Global cross-server interprocess communication based on system
IPC and ZeroMQ to translate events, synchronize state, use reactive
approach and actor-pattern

1. Simple JSON handler
/example/app/examples/simple/jsonPost.json/post.js
module.exports = function(client, callback) {
client.context.data = { a: 1 };
callback();
}
---------------------------------------------------------------
HTTP POST /example/app/examples/simple/jsonPost.json
{
"a": 1
}

2. Simple AJAX handler with template
/examples/simple/ajaxTest.ajax/get.js
client.context.data = {
parameterName: client.query.parameterName,
};
callback();
}
---------------------------------------------------------------
/examples/simple/ajaxTest.ajax/html.template
AJAX Request with parameter returning back in template<br>
parameterName: @parameterName@
---------------------------------------------------------------
HTTP GET
/examples/simple/ajaxTest.ajax?parameterName=parameterValue
AJAX Request with parameter returning back in template<br>
parameterName: parameterValue

3. Client-side example
/js/init.js
$.post('/examples/simple/jsonPost.json',
{ parameterName: "paramaterValue" },
function(res) {
console.log(res.valueLength);
}
);
---------------------------------------------------------------
HTTP POST /example/app/examples/simple/jsonPost.json
{
"status": 1,
"parameterValue": "paramaterValue",
"valueLength": 14,
"requestCounter": 3
}
---------------------------------------------------------------
Console:
14

4. File system access example
/examples/simple/fsAccess.json/get.js
var filePath = client.hostDir+client.path+'/test.txt';
fs.readFile(filePath, 'utf8', function(error, data) {
client.context.data = {
fileContent: data,
dataLength: data.length
};
callback();
});
}
---------------------------------------------------------------
HTTP GET /examples/simple/fsAccess.json
{
"fileContent": "?Example text file",
"dataLength": 18
}

5. HTTP-request from API handle example
/examples/simple/httpRequest.json/get.js
var req = impress.http.request({ hostname: 'google.com',
port: 80, path: '/', method: 'get' },
function(response) {
var data = '';
response.on('data', function(chunk) {data=data+chunk;});
response.on('end', function() {
client.context.data = data;
callback();
});
}
);
req.on('error', function(e) {
client.context.data = "Can't get page";
callback();
});
req.end();
}

6. MongoDB (read) access example
/examples/mongodb/getData.json/get.js
dbAlias.testCollection.find({}).toArray(
function(err, nodes) {
client.context.data = nodes;
callback();
}
);
}
---------------------------------------------------------------
HTTP GET mongodb/getData.json
[
{ "_id": "53547375894c3d3022000001" }
]

7. MongoDB write and metadata examples
/examples/mongodb/insertData.json/get.js
dbAlias.testCollection.insert(client.query, function(err) {
client.context.data = !err;
callback();
});
}
---------------------------------------------------------------
/examples/mongodb/getCollections.json/get.js
dbImpress.connection.collections(function(err, collections) {
var items = [];
for (var i = 0; i < collections.length; i++) {
items.push(collections[i].collectionName);
}
client.context.data = items;
callback();
});
}

8. SQL-query (MySql) access example
/examples/mysql/getCities.json/get.js
dbAlias.query(
'select * from City',
function(err, rows, fields) {
client.context.data = { rows:rows, fields:fields };
callback();
}
);
}

9. Async parallel resource access example
/examples/complex/getFsMongoRequest.json/get.js
impress.async.parallel({
file: function(callback) {
var filePath = client.hostDir+client.path+'/test.txt';
fs.readFile(filePath, 'utf8', function(error, data) {
callback(null, data);
});
},
request: function(callback) {
var req = impress.http.request({ hostname: 'google.com', port: 80,
path: '/', method: 'get' },
function(response) {
var data = '';
response.on('data', function(chunk) { data = data+chunk; });
response.on('end', function() { callback(null, data); });
}
);
req.on('error', function(e) {
callback(null, "Can't get page");
});
req.end();
},
...

...previous example end
/examples/complex/getFsMongoRequest.json/get.js
...
mongo: function(callback) {
dbAlias.testCollection.find({}).toArray(function(err, nodes) {
callback(null, nodes);
});
}
}, function(err, results) {
client.context.data = results;
callback();
});
}
---------------------------------------------------------------------------------
{
"mongo": [
{ "_id": "53547375894c3d3022000001" }
],
"file": "?Example text file",
"request": "<HTML><HEAD><meta http-equiv="content-type" content="text/html;
charset=utf-8">n<TITLE>302 Moved</TITLE></HEAD><BODY>n
<H1>302 Moved</H1>nThe document has movedn
<A HREF="http://www.google.com.ua/?gws_rd=cr&
ei=OWVWU5nHOqOc4wTbjYDgBw">here</A>.rn</BODY></HTML>rn"
}

10. Stateful API handler example
/examples/memory/stateful.json/get.js
application.stateTest =
application.stateTest || { counter: 0, addresses: [] };
application.stateTest.counter++;
application.stateTest.addresses.push(
client.req.connection.remoteAddress
);
client.context.data = application.stateTest;
callback();
}

11. SSE handle example
/examples/events/connect.sse/get.js
client.sse.channel = 'TestEventStream';
callback();
}
---------------------------------------------------------------
/js/init.js
var sse = new EventSource("/examples/events/connect.sse");
sse.addEventListener("TestEventStream", function(e) {
console.dir({
event: e.event,
data: e.data
});
});

12. WebSocket handler example
/examples/events/connect.ws/get.js
var connection = client.res.websocket.accept();
connection.send('Hello world');
connection.on('message', function(message) {
connection.send('I am here');
});
connection.on('close', function(reasonCode, description) {
console.log('disconnected');
});
callback();
}
---------------------------------------------------------------
/js/init.js
ws = new WebSocket("ws://127.0.0.1:80/examples/events/connect.ws");
ws.onopen = function() {};
ws.onclose = function() {};
ws.onmessage = function(evt) {
console.log("Message from server: "+evt.data);
}

API and FS introspection screens

Deployment patterns
• Installation script with deployment recomendations
• Applications Server Configuration /config/*.js
• Start strategies (single, multiple, specialization, sticky)
• Multithreading parameters: cluster.js
• Network interfaces and port configuration: servers.js
• Sandboxes configuration, plugins and access
• Impress Applied Controller configuration: cloud.js
• Logging configuration: log.js
• Application configuration /applications/name/config/*.js
• Database access parameters: databases.js
• Virtualhosts: hosts.js
• URL-rewriting and reverse proxy configuration: routes.js
• Session parameters: sessions.js
• Static files and caching parameters: files.js
• Application specific configuration files

Server installation (node.js + Impress)
CentOS 6.5 (64bit) minimal
curl http://.../impress/install.sh | sh
---------------------------------------------------------------
#!/bin/bash
yum -y update
yum -y install wget
yum -y groupinstall "Development Tools"
cd /usr/src
wget http://nodejs.org/dist/v0.10.26/node-v0.10.26.tar.gz
tar zxf node-v0.10.26.tar.gz
cd node-v0.10.26
./configure
make
make install
ln -s /usr/local/bin/node /bin
ln -s /usr/local/bin/npm /bin
mkdir /impress
cd /impress
npm install impress

Application Server as Linux Daemon
If installing Impress into absolute path /impress
Run /impress/bin/install.sh for:
• Setup and configure as Linux daemon
• Run at system startup
• Auto-restart daemon workers on fails
Run /impress/bin/uninstall.sh for:
• Stop Application Server
• Remove from system startup
• Remove Daemon from system
After install as a service (daemon) you can use:
service impress start
service impress stop
service impress restart
service impress update
service impress status

Application Server Configuration
/config/cloud.js
module.exports = {
name: "PrivateCloud",
type: "standalone",
controller: "127.0.0.1",
pubSubPort: "3000",
reqResPort: "3001",
health: "2s"
}
---------------------------------------------------------------
/config/cluster.js
module.exports = {
check: "http://127.0.0.2/",
name: "C1",
cookie: "node",
strategy: "multiple", // single, specialization, sticky
workers: os.cpus().length,
gcInterval: 0
}

Network interfaces & ports config
/config/servers.js
module.exports = {
www: {
protocol: "http",
address: "127.0.0.1",
port: 80,
applications: ["example", "host2"],
nagle: true,
slowTime: "1s"
},
ssl: {
protocol: "https",
address: "127.0.0.1",
port: 443,
key: "example.key",
cert: "example.cer"
}
}

Plugins configuration
/config/plugins.js
module.exports = [
"db",
"db.schema",
"db.mongodb",
"db.memcached",
"db.mysql",
"db.mysql.schema",
"impress.log",
"impress.security",
"impress.security.mongodb",
"impress.mail",
"impress.uglify",
"impress.health",
"impress.cloud",
"impress.geoip",
"impress.websocket",
"impress.sse"
]

Logging and sandbox configuration
/config/log.js
module.exports = {
keepDays: 10,
writeInterval: "3s",
writeBuffer: 64*1024,
fileTypes: [ "access", "error", "debug", "slow" ]
}
---------------------------------------------------------------
/config/sandbox.js
module.exports = { modules: [
'global', 'console', 'process', 'impress',
'db', 'domain', 'crypto', 'geoip',
'os', 'Buffer', 'stream', 'nodemailer',
'net', 'http', 'https', 'dgram',
'dns', 'url', 'path', 'fs',
'util', 'events', 'iconv', 'querystring',
'zlib', 'async'
]}

Virtualhosts and URL-rewriting config
/applications/applicationName/config/hosts.js
module.exports = [
"127.0.0.1",
"mydomain.com",
"*.domainname.com",
]
---------------------------------------------------------------
/applications/applicationName/config/routes.js
module.exports = [
{ url: "/api/(one|two)/(.*)",
rewrite: "/example/[1].json?par1=[2]"
},
{ url: "/api/(name1|name2|name3)/(.*)",
rewrite: "/api/[1]/[2]",
host: "example.com",
port: 80,
slowTime: "1s"
}
]

Database access configuration
/applications/applicationName/config/databases.js
module.exports = {
mongoTest: {
url: "mongodb://hostName:27017/databaseName",
slowTime: "2s",
collections: ["collection1", "collection2"],
security: true,
alias: "alias1"
},
system: {
url: "mysql://user:password@localhost/dbName",
slowTime: 1000,
alias: "aliasName"
}
}

Session and static files serving config
/applications/applicationName/config/sessions.js
module.exports = {
anonymous: true,
cookie: "SID",
characters: "ABCDEFGH...fghijkl...456789",
length: 64,
persist: true,
database: "impress"
}
---------------------------------------------------------------
/applications/applicationName/config/files.js
module.exports = {
minify: false,
static: [
"*/css/*", "*/images/*", "*/js/*",
"*/favicon.ico", "*/favicon.png"
]
}

Thanks for attention!
Questions please
Timur Shemsedinov
Research Institute of System Technologies (UA, Kiev), MetaSystems Inc.
mailto:timur.shemsedinov@gmail.com
http://habrahabr.ru/users/marcusaurelius/
https://www.npmjs.org/package/impress
https://github.com/tshemsedinov/impress

Rapid API development examples for Impress Application Server / Node.js (jsfwdays 2014)

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