Beer for Issue!

Hi there.. It’s been a while and I’m still pretty busy, but I feel like I have to write something this very sunny afternoon.
There are a lot of projects in the pipeline, a few will come out sooner or later :)
One project which is still making my head go up and down and left and right is Transport. I somehow managed to get on the shortlist of this years Best of Swiss Web. Besides that, I found a still secret partner for the work on Transport. There has been a lot of development, of which not all is on github yet – some parts are just not ready for open source deployment. (But they will be!)
Today, I want to talk about my beta testers – they are great. Most of them anyway :)

I’m facing two problems with them though. First, I don’t know all of them – which is unfortunate. There are some I just cannot meet because they live in the south of Uguhagdarbia (not quite..) but there are  others which live in the very same city – Zurich – and I still haven’t managed to meet them.

Second, some of them just want to have an application before everyone else does – (no offense guys..) – and what I want in return is feedback – and not always get it. However, there are some very serious beta testers and I really want to thank you :)

This night, I had an insanly great idea to solve both problems at once and actually solve a third problem: get more testers :)

So what is it about? There have been rumors, that Transport will be ready at the end of march, and so I will need testers in the next few weeks.
This is why I proudly announce the “Beer for Issue” program :) What is that? My idea is: If you sign up until the 20th of march on beta[AT]codesofa.com with your UDID, name and e-mail (see Apply for Beta) and you are among the first 70 to sign up, then you get into the “program”. After that, you will receive a copy of “Transport.app” Beta for the iPhone somewhen after the 20th.

`HOLY CRAP WHERE IS THAT BEER!` – yes, we are coming to it. After that, you will receive instructions of how to report bugs/issues/whatsoever to me :) Since I really appreciate your time and haven’t figured out a way to show that to you, I offer Beer. Free Beer actually. :) The exact rules have to be determined after the signup is completed, but I plan to give out a beer for every fibonacci number of issues you report, starting at 3.. As long as they are not a duplicate. With “improvement” requests, I’m not so sure yet. That will be a mater of personal oppinion, if they are great, I’ll buy you 2 beers, if they are ridiculous, you’ll have to buy me 4 to make me implement it ;)

Let’s make an example: You report 3 issues – get 1 beer, 4 issues – still only 1, 5 issues (2+3) – get 2 beers, 6 & 7 issues – 2 beers, 8 issues – 3 beers etc. Maybe there will be more beer – I don’t know yet :)

`IS HE INSANE?!` – No, not at all. This will force me to write good code, so I don’t have to buy a lot of beers and besides that, I get to know all of you :) It’s like a release party.. But more fun because everyone worked on it..

In short:

  • Write me an E-Mail with you iPhone/iPod UDID, your name and your e-mail address until march 20th, 2009 to beta[AT]codesofa.com
  • Report issues on “Transport” iPhone app.
  • Get paid in beer – and yes, for ladies there will be a special arrangement possible :)

Have fun.

btw.: There is some special ruling for the last testing-period testers, I will figure something out – but you’ll get more ;)

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Filed under: Information, Transport, iPhone on February 27, 2009 at 3:42 pm by marc.
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done.

 So much for tonight. Thanks Stefan :)

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Filed under: GottaGo, Information, Transport, iPhone on October 8, 2008 at 1:37 am by marc.
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A short note on CLLocation / CLLocationManager

**** DEPRECATED **** Use http://liip.to/ilocator

Well.. I’ve been testing this Locator quite a while now. Today I had my final attempt, to find out, why I always got either a cached location or an extremely inaccurate location.

Today, I went out with my notebook (yes, there where the sun is..) to debug.

The example of apple says, to check the timestamp of the newLocation. (It should be less than 5..). Yeah well, guess what – it is sometimes 0 in a cached location. And somehow it’s sometimes just a bit over 5 and you’ll have to wait forever to get a new location.


- (void)locationManager:(CLLocationManager *)manager
    didUpdateToLocation:(CLLocation *)newLocation
           fromLocation:(CLLocation *)oldLocation
{
    NSDate* eventDate = newLocation.timestamp;
    NSTimeInterval howRecent = [eventDate timeIntervalSinceNow];

    if (howRecent < -0.0 && howRecent > -10.0) {
        [manager stopUpdatingLocation];

        // USE THE FORCE OF THE LOCATION!
    }
}

This one should work. Maybe that location stuff is working in the U.S. but it wasn’t in Switzerland..

P.S.: I had another issue with a pwned iPhone today. NSXMLParser throw me errors back and I didn’t know why.. I still don’t know why, I guess it had to do with the libxml2 update I did. Workaround? Restore, works fine now.

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Filed under: How-To, Tech on July 25, 2008 at 12:41 am by marc.
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Make NSXMLParser your friend..

As promised, here is a little How-I-did-it / How-To.

First off: I am not an experienced SAX-User.. So this approach might be packing the problem at it’s tail, but this is how DOM-Users feel comfortable with ;)

Let’s assume we want to parse the following XML:

tranist.xml

<root>
    <schedules>
        <schedule id="0">
            <from>SourceA</from>
            <to>DestinationA</to>
            <links>
                <link id="0">
                    <departure>2008-01-01 01:01</departure>
                    <arrival>2008-01-01 01:02</arrival>
                    <info>With food</info>
                    <parts>
                        <part id="0">
                            <departure>2008-01-01 01:01</departure>
                            <arrival>2008-01-01 01:02</arrival>
                            <vehicle>Walk</vehicle>
                        </part>
                        <part id="1">
                            <departure>2008-01-01 01:01</departure>
                            <arrival>2008-01-01 01:02</arrival>
                            <trackfrom>1</trackfrom>
                            <trackto>2</trackto>
                            <vehicle>Train</vehicle>
                        </part>
                    </parts>
                </link>
                <link id="1">
                    ...
                </link>
                <link id="2">
                    ...
                </link>
            </links>
        </schedule>
        <schedule id="1">
            ...
        </schedule>
        <schedule id="2">
            ...
        </schedule>
    </schedules>
</root>

In human readable format, this means: We have multiple schedules with from/to etc. These schedules consist of multiple links (different connections for the same route) with departure/arrival etc. These links consist then of multiple parts/sections with various elements which are not sure to be there..

With the let’s find the element called ‘part’ – approach, you won’t get anywhere..

The Basics

So what do we want to achieve? We want a list/array of Schedules, which have the given members. On member is a list/array of Links, also consisting of the given members and a list/array of parts with the respective members.

This is also the basic idea behind my approach: for every new node-container, use a new class/object (an array will also work, but it’s kinda crap..)

Now we have a Schedule class, a Link class and a Part class.

This is an example of the Link class interface:

Link.h

#import "Part.h"

@interface Link : NSObject {
    NSString *departure;
    NSString *arrival;
    NSString *info;
    NSMutableArray *parts;
}

@property (nonatomic, retain) NSString *departure;
@property (nonatomic, retain) NSString *arrival;
@property (nonatomic, retain) NSString *info;
@property (readonly, retain) NSMutableArray *parts;

- (void)addPart:(Part *)part;

@end

We use an accessor method for the parts, because it just feels better when dealing with arrays. (Instead of later using [foo.myArray addObject:..] we have [foo addMe:..])

Also we make it easier for us, using retain properties..

The Parser setup

A short introduction into SAX:

The parsing goes node by node and is not nesting-sensitive. That means that first we get root, then schedules, then schedule, then from, then to, then links, then link, then departure etc. As soon as the parser returns you the node for example, you don’t know anymore in what schedule you were. As long as you have a clearly defined structure where always every element must be present, you could do this using a counter, but as soon as you have multiple nodes with no defined count, you have a problem.

What we do is known as recursive parsing. What does this mean? We implement some kind of memory.

In our parser, we have 4 members and 1 method (to make actual use of the parser..):

@property (nonatomic, retain) NSMutableString *currentProperty;
@property (nonatomic, retain) Schedule *currentSchedule;
@property (nonatomic, retain) Link *currentLink;
@property (nonatomic, retain) Part *currentPart;
@property (nonatomic, readonly) NSMutableArray *schedules;

- (void)parseScheduleData:(NSData *)data parseError:(NSError **)error;

(Yes, this needs to be a NSMutableString..)

Your parseScheduleData method should look similar to the following:

parseJourneyData

- (void)parseJourneyData:(NSData *)data parseError:(NSError **)err {
    NSXMLParser *parser = [[NSXMLParser alloc] initWithData:data];

    self.schedules = [[NSMutableArray alloc] init]; // Create our scheduler list

    [parser setDelegate:self]; // The parser calls methods in this class
    [parser setShouldProcessNamespaces:NO]; // We don't care about namespaces
    [parser setShouldReportNamespacePrefixes:NO]; //
    [parser setShouldResolveExternalEntities:NO]; // We just want data, no other stuff

    [parser parse]; // Parse that data..

    if (err && [parser parserError]) {
        *err = [parser parserError];
    }

    [parser release];
}

Now we need those delegate methods.

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string

This function is called by the parser, when it reads something between nodes. (Text that is..) Like with blah it would read “blah”. It is possible, that this method is called multiple times in one node. As you will see later, we define the property “currentProperty” only if we find a node, we care about. That’s why we test it against this property to make sure, that we need this property. This will then look something like this:

Parser

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
{
    if (self.currentProperty) {
        [currentProperty appendString:string];
    }
}

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict

This is called, when the parser finds an opening element. In this case, we have a few cases, we need to distinguish. These are:

It’s standard property in the schedule (like <form> etc.) or it’s a deeper nested node (like <links>), the same for all the other nodes.

How to? We define, that we only set a member, if we are in that node. That means, only when we have entered a <part>, then currentPart is set, otherwise it’s nil. The same with the others.

We do then need to check them in reverse order of their nesting level.. Why? Because if we would check for currentLink before currentPart, currentLink would also evaluate to YES/True and hence we will have a problem if their are elements with the same name. If we aren’t in any node, then there is probably a new main node comming -> in the else..

When we hit a nested node, we need to allocate the respective member of our class, so we can use it when the parser gets deeper into it.

This will look like this:

Parser

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict {
    if (qName) {
        elementName = qName;
    }

    if (self.currentPart) { // Are we in a
        // Check for standard nodes
        if ([elementName isEqualToString:@"departure"] || [elementName isEqualToString:@"arrival"] || [elementName isEqualToString:@"vehicle"] || [elementName isEqualToString:@"trackfrom"] || [elementName isEqualToString:@"trackto"] ) {
            self.currentProperty = [NSMutableString string];
        }
    } else if (self.currentLink) { // Are we in a
        // Check for standard nodes
        if ([elementName isEqualToString:@"departure"] || [elementName isEqualToString:@"arrival"] || [elementName isEqualToString:@"info"]) {
            self.currentProperty = [NSMutableString string];
        // Check for deeper nested node
        } else if ([elementName isEqualToString:@"part"]) {
            self.currentPart = [[Part alloc] init]; // Create the element
        }
    } else if (self.currentSchedule) { // Are we in a  ?
        // Check for standard nodes
        if ([elementName isEqualToString:@"from"] || [elementName isEqualToString:@"to"]) {
            self.currentProperty = [NSMutableString string];
        // Check for deeper nested node
        } else if ([elementName isEqualToString:@"link"]) {
            self.currentLink = [[Link alloc] init]; // Create the element
        }
    } else { // We are outside of everything, so we need a
        // Check for deeper nested node
        if ([elementName isEqualToString:@"schedule"]) {
            self.currentSchedule = [[Schedule alloc] init];
        }
    }
}

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName

Basically, the same things apply as for didStartElement above. This time, we need to clean things up and assign them if they are set :) This is a bit a pitty, since it’s a lot of code.. *(for not so much)

It’s the same checker-structure..

If we are in a deeper nested node (like <Link>) and we hit an ending element of that nested node (like </Link>), Then we need to add this element to the parent (like <Schedule>) and set it to nil

See yourself:

Parser

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {
    if (qName) {
        elementName = qName;
    }

    if (self.currentPart) { // Are we in a
        // Check for standard nodes
        if ([elementName isEqualToString:@"departure"]) {
            self.currentPart.departure = self.currentProperty;
        } else if ([elementName isEqualToString:@"arrival"]) {
            self.currentPart.arrival = self.currentProperty;
        } else if ([elementName isEqualToString:@"vehicle"]) {
            self.currentPart.vehicle = self.currentProperty;
        } else if ([elementName isEqualToString:@"trackfrom"]) {
            self.currentPart.trackfrom = self.currentProperty;
        } else if ([elementName isEqualToString:@"trackto"]) {
            self.currentPart.trackto = self.currentProperty;
        // Are we at the end?
        } else if ([elementName isEqualToString:@"part"]) {
            [currentLink addPart:self.currentPart]; // Add to parent
            self.currentPart = nil; // Set nil
        }
    } else if (self.currentLink) { // Are we in a
        // Check for standard nodes
        if ([elementName isEqualToString:@"departure"]) {
            self.currentLink.departure = self.currentProperty;
        } else if ([elementName isEqualToString:@"arrival"]) {
            self.currentLink.arrival = self.currentProperty;
        } else if ([elementName isEqualToString:@"info"]) {
            self.currentLink.info = self.currentProperty;
        // Are we at the end?
        } else if ([elementName isEqualToString:@"link"]) {
            [currentSchedule addPart:self.currentLink]; // Add to parent
            self.currentLink = nil; // Set nil
        }
    } else if (self.currentSchedule) { // Are we in a  ?
        // Check for standard nodes
        if ([elementName isEqualToString:@"from"]) {
            self.currentSchedule.from = self.currentProperty;
        } else if ([elementName isEqualToString:@"to"]) {
            self.currentSchedule.to = self.currentProperty;
        // Are we at the end?
        } else if ([elementName isEqualToString:@"schedule"]) { // Corrected thanks to Muhammad Ishaq
             [schedules addObject:self.currentSchedule]; // Add to the result node
             self.currentSchedule = nil; // Set nil
        }
    }

    // We reset the currentProperty, for the next textnodes..
    self.currentProperty = nil;
}

Finally..

Well, that’s it. You can expand / shrink this principle as you like. You can also add a maxElements counter, like in the SeismicXML example of the iPhone SDK to get only a certain number of elements. You can abort the parser with [parser abortParsing]; It is important, that you don’t abort while in a deeper nested node, because this could lead to inconsistencies. You will need to skip them..

Please note, that I wrote this, while watching TV, so you may need to fix some syntax errors ;) But I hope you get the idea..

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Filed under: How-To, Tech, iPhone on July 23, 2008 at 2:27 am by marc.
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GottaGo – Why it’s not out there yet..

Well, first of all, thanks for the great response on the first sneak preview of `GottaGo’ – even though some people thought I’ve been on weed during the video presentation – I wasn’t :) It’s quite difficult to talk in presentation-loudness at 2am where I live..

So, what kept me from submitting to the AppStore?
Well, first of all I had to get my hands on a JesusPhone.. One I could work with. – Done -

You might say – there is a Simulator, the phone should be a small stage for the final testing. Yes, that’s what I thought.

Apparently, Apple allowed system libraries to be compiled into your software, while using the Simulator. Well – and since NSXMLDocument is not included in the final build of the SDK – I’m quite frankly – doomed now when I try to compile on the iPhone.

My options now are:

  • libxml2 wrapper:
    • fix the iconara to work with iphone (linker errors)
    • write my own (jeeez)
  • use plain libxml2:
    • spaghetti code
    • wheee
  • use my own webservice to aggregate and send a small xml and parse via NSXMLParser (SAX):
    • sbb might block me for too many requests
    • bottleneck
    • yet another system that may fail

I think I’m going with the own webservice. It doesn’t feel right though. I think in a device that powerful, there should be a simple implementation of the DOM. I see the iPhone as a mobile device which should profit as much as possible from different webservices and cache only necessary things. Obviously Apple is more concerned about OpenGL(-Games) than about web-service access.

If there is a libxml wizard out there, feel free to contact me :)
I’ll try to focus on libxml for some additional hours and if there is no hope, I’ll set up my own webservice. I hope I’ll be able to submit GottaGo to the AppStore this weekend.

And to clear some things up:

  • GottaGo will be free of charge
  • GottaGo will only work in Switzerland for now

UPDATE Well.. After some hours of hacking, I was able to put GottaGo on my iPhone in a light-version. That means: location tracking and station finding, but no SBB querying for now. For SBB, I will probably have to proxy the requests since their response html is not even valid html.. But now there is some pressure on my shoulders. I was able to submit to AppStore. The requested release day is: July 19, so stay tuned :)

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Filed under: Tech, iPhone on July 17, 2008 at 2:22 am by marc.
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