I Phone On Rails

iPhone on Rails

Mike Clark clarkware.com

Hosted Rails App?

Fielded iPhone App?

Neither?!

Rails
Installation

$ sudo gem update --system
$ sudo gem install rails
$ sudo gem update rake
$ sudo gem update sqlite3-ruby

Rails
Scaffold App

$ rails expenses
$ cd expenses

$ script/generate scaffold expense
name:string amount:decimal

$ rake db:migrate

$ script/server

http://localhost:3000/expenses

Rails Resource
Routes

ActionController::Routing::Routes.draw do |map|
map.resources :expenses
end

Rails Resource
CRUD Routing

POST /expenses/3

GET /expenses

PUT /expenses/3

DELETE /expenses/3

Rails Resource
Controller

class ExpensesController < ApplicationController

# GET /expenses
def index
end

# POST /expenses
def create
end

# GET /expenses/3
def show
end

# PUT /expenses/3
def update
end

# DELETE /expenses/3
def destroy
end

end

Rails Resource
Model

class Expense < ActiveRecord::Base
validates_presence_of :name
validates_numericality_of :amount,
:greater_than_or_equal_to => 0
end

Expense.create(:name => "iPod touch", :amount => 249.00)

Expense.find(3)

Expense.update(3, :amount => 199.00)

Expense.destroy(3)

Rails Resource
View


Name:
<%=h @expense.name %>



Amount:
<%=h @expense.amount %>


<%= link_to 'Edit', edit_expense_path(@expense) %> |
<%= link_to 'Back', expenses_path %>

Rails
CRUD Conventions

POST GET PUT DELETE

create find update destroy

INSERT SELECT UPDATE DELETE

>> print Expense.find(3).to_xml

<?xml version="1.0" encoding="UTF-8"?>
<expense>
<id type="integer">2</id>
<name>iPod touch</name>
<amount type="decimal">199.0</amount>
<created-at type="datetime">2009-09-15T16:01:54Z</created-at>
<updated-at type="datetime">2009-09-15T16:01:54Z</updated-at>
</expense>

>> print Expense.find(3).to_json

{"expense":
{"id":2,
"name":"iPod touch",
"amount":199.0,
"created_at":"2009-09-15T16:01:54Z",
"updated_at":"2009-09-15T16:01:54Z"
}
}

Rails Resource
Multi-Format Responses


def show
@expense = Expense.find(params[:id])

respond_to do |format|
format.html # show.html.erb
format.xml { render :xml => @expense }
format.json { render :json => @expense }
end
end

end

GET /expenses/3.{html|xml|json}

Rails
Security Tip

class User < ActiveRecord::Base

def to_xml(options={})
options[:only] = [:id, :name, :screen_name]
super(options)
end

end

iPhone CRUD
Roll Your Own

@implementation Expense

static NSString *siteURL = @"http://localhost:3000";

- (NSString *)params {
return [NSString stringWithFormat:@"{"expense":{"name":"%@","amount":"%@"}}",
self.name, self.amount];
}

- (void)createRemote {
NSString *url = [NSString stringWithFormat:@"%@/expenses.json", siteURL];
[Resource post:[self params] to:url];
}

+ (NSArray *)findAllRemote {
NSString *url = [NSString stringWithFormat:@"%@/expenses.json", siteURL];
NSString *jsonString = [Resource get:url];
NSArray *expenses = // create expenses from JSON string
return expenses;
}

- (void)updateRemote {
NSString *url = [NSString stringWithFormat:@"%@/expenses/%@.json", siteURL, self.expenseId];
[Resource put:[self params] to:url];
}

- (void)destroyRemote {
NSString *url = [NSString stringWithFormat:@"%@/expenses/%@.json", siteURL, self.expenseId];
[Resource delete:url];
}

@end

HTTPRiot

Supports generic RESTful operations
Converts JSON response to NSDictionary
You decide what to do with the data
Asynchronous

http://github.com/Caged/httpriot

HTTPRiot
Conﬁguration and Requests

[HRRestModel setDelegate:someObject];
[HRRestModel setBaseURL:[NSURL URLWithString:@"http://your-server/api"]];

[HRRestModel getPath:@"/expenses.json" withOptions:nil object:nil];

NSDictionary *options =
[NSDictionary dictionaryWithObject:[expense JSONRepresentation] forKey:@"body"];
[HRRestModel postPath:@"/expenses" withOptions: options object:nil];

NSDictionary * options =
[NSDictionary dictionaryWithObject:[expense JSONRepresentation] forKey:@"body"];
[HRRestModel putPath:@"/expenses/3" withOptions:options object:nil];

[HRRestModel deletePath:@"/expenses/3" withOptions:nil object:nil];

HTTPRiot
Callbacks

- (void)restConnection:(NSURLConnection *)connection
didReturnResource:(id)resource
object:(id)object {

for (id item in resource) {
Expense *expense = [[Expense alloc] initWithDictionary:item];
// do something with expenses
}
}

didFailWithError:(NSError *)error
object:(id)object {
// Handle connection errors
}

didReceiveError:(NSError *)error
response:(NSHTTPURLResponse *)response
object:(id)object {
// Handle invalid responses: 404, 500, and so on
}

didReceiveParseError:(NSError *)error
responseBody:(NSString *)string {
// Request was successful, but couldn't parse the data returned by the server
}

ASIHTTPRequest

Super ﬂexible with lots of features
File uploads, progress indictors, etc.
Uses CFNetwork API
Asynchronous

http://github.com/pokeb/asi-http-request

ASIHTTPRequest
Usage

- (void)sendRequest {
NSURL *url = [NSURL URLWithString:@"http://your-server.com/expenses.json"];
ASIHTTPRequest *request = [[ASIHTTPRequest alloc] initWithURL:url];
[request setDelegate:self];
[request setDidFinishSelector:@selector(requestSucceeded:)];
[request setDidFailSelector:@selector(requestFailed:)];
[[self queue] addOperation:request];
[request release];
}

- (void)requestSucceeded:(ASIHTTPRequest *)request {
NSString *response = [request responseString];
}

- (void)requestFailed:(ASIHTTPRequest *)request {
NSError *error = [request error];
}

ObjectiveResource

Objective-C port of ActiveResource
Serializes to/from objects (XML or JSON)
Assumes Rails RESTful conventions
Asynchronous option in 1.1 branch

http://github.com/yfactorial/objectiveresource

ObjectiveResource
Remote Resource

#import "ObjectiveResource.h"

@interface Expense : NSObject {
NSString *expenseId;
NSString *name;
NSString *amount;
NSDate *createdAt;
NSDate *updatedAt;
}

@property (nonatomic, copy) NSString *expenseId;
@property (nonatomic, copy) NSString *name;
@property (nonatomic, copy) NSString *amount;
@property (nonatomic, retain) NSDate *createdAt;
@property (nonatomic, retain) NSDate *updatedAt;

@end

* NSObject+ObjectiveResource category

ObjectiveResource
Conﬁguration


[ObjectiveResourceConfig setSite:@"http://your-server.com/"];
[ObjectiveResourceConfig setResponseType:JSONResponse];

ObjectiveResource
CRUD Operations

NSArray *expenses = [Expense findAllRemote];

Expense *expense = [[Expense alloc] init];
expense.name = @"iPod touch";
[expense createRemote];

Expense *expense = [Expense findRemote:@"3"];
expense.name = @"iPhone";
[expense updateRemote];

[expense destroyRemote];

ObjectiveResource
Asynchronous Way

[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
[[ConnectionManager sharedInstance] runJob:@selector(loadExpenses)
onTarget:self];

* NSInvocationOperation in an NSOperationQueue

- (void)loadExpenses {
self.expenses = [Expense findAllRemote];

[self.tableView performSelectorOnMainThread:@selector(reloadData)
withObject:nil
waitUntilDone:NO];

[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
}

Rails
Nested Resources

ActionController::Routing::Routes.draw do |map|
map.resources :budgets, :has_many => :expenses
end

Rails
Nested Resource


before_filter :find_budget

def show
@expense = @budget.expenses.find(params[:id])

format.html
format.xml { render :xml => @expense }
format.json { render :json => @expense }
end
end

private

def find_budget
@budget = current_user.budgets.find(params[:budget_id])
end

end

GET /budgets/6/expenses

ObjectiveResource
Nested Resources

@implementation Budget

@synthesize budgetId;

- (NSArray *)findAllExpenses {
return [Expense findRemote:[NSString stringWithFormat:@"%@/%@",
self.budgetId, @"expenses"]];
}

@end

GET /budgets/6/expenses

ObjectiveResource
Nested Resources

@implementation Expense

@synthesize expenseId;
@synthesize budgetId;

+ (NSString *)getRemoteCollectionName {
return @"budgets";
}

- (NSString *)nestedPath {
NSString *path = [NSString stringWithFormat:@"%@/expenses", self.budgetId];
if (self.expenseId) {
path = [path stringByAppendingFormat:@"/%@", self.expenseId];
}
return path;
}

- (BOOL)createRemoteWithResponse:(NSError **)aError {
return [self createRemoteAtPath:[[self class] getRemoteElementPath:[self nestedPath]]
withResponse:aError];
}

- (BOOL)updateRemoteWithResponse:(NSError **)aError {
return [self updateRemoteAtPath:[[self class] getRemoteElementPath:[self nestedPath]]
}

- (BOOL)destroyRemoteWithResponse:(NSError **)aError {
return [self destroyRemoteAtPath:[[self class] getRemoteElementPath:[self nestedPath]]
}

@end
* yeah, itʼs kinda clunky

Rails
Authentication

class BudgetsController < ApplicationController

before_filter :authenticate

def index
@budgets = current_user.budgets.all
end

def show
@budget = current_user.budgets.find(params[:id])
end

private

def current_user
@current_user ||= User.find(session[:user_id])
end

end

Rails
Authentication

def authenticate
return if session[:user_id]

format.html do
redirect_to login_url
end
format.any(:xml, :json) do
user = authenticate_with_http_basic do |username, password|
User.authenticate(username, password)
end
if user
session[:user_id] = user.id
else
request_http_basic_authentication
end
end
end
end

ObjectiveResource
Conﬁguration


[ObjectiveResourceConfig setSite:@"http://your-server.com/"];
[ObjectiveResourceConfig setResponseType:JSONResponse];
[ObjectiveResourceConfig setUser:@"John"];
[ObjectiveResourceConfig setPassword:@"Appleseed"];

RESTful web services are
resource based, stateless,
and scaleable

Hands-on iPhone and Rails
training from the folks who
wrote the books

pragmaticstudio.com

I Phone On Rails

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