Author: stlplace

iPhone app Software development

Code signing error in Xcode

Post author By stlplace
Post date February 6, 2013
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Reading Time: 2 minutes

(Update 08-Dec-2020) Things I learned today (or tomorrow am 🙂

One team can have at most two distribution certs
In Xcode sign in as agent without the (mail.com or gmail.com after @) because it appears my apple id is just the id without all the @ + dot com stuff. That alone cost me probably one hour. Plus the one hour I tried to export cert in old MacBook, then move it over to the new MacBook. So totally 2 hours wasted… after those two steps, I was able to go back to automatically signing and validate my archive (ipa) for myNestEgg…

Managing a Distribution Certificate

No signing certificate “iOS Distribution” found

Create, export, and delete signing certificates

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For organizations, if a distribution certificate is missing a private key or not in your keychain, you can email the creator of the signing certificate. Ask the creator to export the signing certificate on their Mac so you can install it on your Mac. (To install a certificate in your keychain, double-click the exported certificate file.)

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What is app signing?

Creating the iOS Distribution Certificate

iOS – Creating a Distribution Certificate and .p12 File

(Original 06-Feb-2013) Had my share of code signing problem (esp. the enterprise distribution certificate) in my Xcode development. Luckily, stackoverflow rescued me as always. It seems a lot problem is due to the Xcode upgrade, project name change, provision profile/distribute certificate expiring etc. And the solution is usually delete or comment out the offending line. Like below. To go to the project file, I usually do in the command line, “cd projectName.xcodeproj”, then “vi project.pbxproj”.

http://stackoverflow.com/questions/1760518/codesign-error-provisioning-profile-cannot-be-found-after-deleting-expired-prof

http://stackoverflow.com/questions/5758154/code-sign-error-provisioning-profile-cant-be-found

I encountered another problem related to the provisioning profile expiration, the distribute certificate appears twice in the Keychain, even after I deleted it explicitly. It turns out the old distribute certificate came back after I opened the project in Xcode (presumedly it came back when the old provision profile associated with the project got loaded). So the workaround is to delete the old distribute certificate again after opening the project in Xcode.

http://stackoverflow.com/questions/5932522/codesign-error-certificate-identity-appearing-twice

Btw, saw an interesting idea from Mobile Iron regarding the enterprise distribution certificate. Normally the certificate expires in a year. In last 30 days it will prompt the user something like “the provision profile will expire in a few days…”, not good user experience. There is no way to renew it before it expires either. So the workaround suggested by MI is create 2 certificates, and create the second 6 months before the expiration and have user update the app. This way, essentially the app got extended 6 months. And so on. There is one catch in Xcode 4.3.3 I am using. It only recognizes the provision profile that was created earlier (or expires earlier). The workaround there is delete the earlier provision profile 😀

Tags code, mobile app management, signing, xcode

Software development Web Windows

Consuming a PHP SOAP web service from C# client

Post author By stlplace
Post date January 16, 2013
1 Comment on Consuming a PHP SOAP web service from C# client

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I need to create a SOAP client in C#, and in order to test it I need a SOAP web service. Since my hosting company uses MySQL/PHP technology stack, I am using this PHP Soap web service example.

For the C# soap client, I am following this example on stackoverflow. But there is one problem when I tried to run the example. I got the error (exception) like the following:
The content type text/xml; charset=ISO-8859-1 of the response message does not match the content type of the binding (text/xml; charset=utf-8). If using a custom encoder, be sure that the IsContentTypeSupported method is implemented properly.

Again I found this thread on stackoverflow which seems relevant. It talked about the custom message encoder developed by Microsoft, and Paul Morgado’s addition to the CustomTextMessageEncoder class (just add his method at the end of the class). There is one more thing, the configuration file for the app. In my case, it’s something like the following: (note the messageVersion and bindingElementExtensions definition, there was some error in the Microsoft documentation regarding the latter one).

Software development

Set up SVN (Subversion) on local machine (Windows)

Post author By stlplace
Post date January 10, 2013
1 Comment on Set up SVN (Subversion) on local machine (Windows)

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I need to do some development work on Windows, using Visual Studio. I like to have a simple source code control system, in recent years I have used CVS, Subversion and git (on Mac). I did a google search on Subversion and found some instructions regarding setting up Subversion.

Setting up Subversion on Windows

and this one

Installing and Configuring SVNServe and TortoiseSVN on Windows

Download/install the SVN server and starting the windows service was relatively straightforward. So as the Tortoise SVN client. Couple things keep in mind:

1) Some sites requires registration or install additional software, I chose sites that does not require registration.

2) I found sometimes I can not open up svn://localhost successfully, in the same command prompt window where I start the SVN service. After I close the command prompt and tried again, it worked. The commands I used are:

set SVN_EDITOR=c:\windows\system32\notepad.exe
svn mkdir svn://localhost/myproject

401k and Personal Finance Career Life

2012 Year in Review

Reading Time: 3 minutes

I took this cue from Kurby Turner, the independent Mac/iOS developer, as I think it might be helpful to reflect a year’s work, life, effort, etc. As the old Chinese saying goes “Ji Wang Kai Lai” (learn from past, and look forward to the future).

New job: Software Development
Today is my one year anniversary at my new employer. Looking back, from the initial ramp up to more comfortable work on my own pace, and then deliver the first iOS (iPad) app to the field, back end work, report work and support. I feel good about my effort and the support I got from my coworkers. Sometimes my wife will ask me “why it took so long for you to complete a project”? Because it’s not trivial to do it.

I also wrote a few blog posts on iOS app development, and the back end (.Net) web service. I plan to do the same as times goes. Generally speaking, now I have more confidence doing customized app development, full life cycle, and from front to back end (all tiers).

Family
Our daughter goes to the Hope Montessori Infant Toddler Community at Creve Coeur (off Manson road, near Olive Blvd). We are truly blessed with the teachers and staffs at the Hope family (I consider them as family, both adults and children, because sometimes they are better than family 🙂 . Serenity (Yoyo) learned English and all kinds of things there, which laid a good foundation for her future. For us, we learned parenting lessons there. Sometimes I wonder how much quality time I spent there, from afternoon pickup, to field trip, to social (work-day, Fettuccine, Montessori and Vino, the FMV movie). We watched the FMV movie with great fun, my wife and my friends (couple) did not attend the FMV event, and really enjoyed the movie after I showed them.

Trips
We did one family vacation, and I had 2 business trips in year 2012. We went to Orange Beach, Alabama in the Memorial Day weekend, with Chinese friends. We drove there. It’s funny Yoyo would not go to bathroom on the road, she wants to use bathroom in the hotel or condo (destination). For the business trip, I visited 2 mines in West Virginia, the 2 hours I spent in underground mine is both interesting and a bit unsettling. That’s the first time I visited mines (both surface and underground). In November I visited Las Vegas, stayed in Palazzo (Venetian), which I stayed 3 years ago when I attended AU (Autodesk University, the developer/user conference) in 2009.

Personal Finance
As I wrote this post, I found I made both good moves and bad moves on this topic. I did well in 401k accounts (because I did nothing). But not in the Scottrade brokerage and IRA accounts (because I tried to do too much). Overall I still did ok, because majority of my assets are in 401k (both existing accounts and new account).

Today (01-03-2012) as I listened to Charlie Ellis on the Consuelo WealthTrack podcast, I can not agree more on one comment from Charlie: we all strive to be above average in school or at work. In investing being average is actually not too bad. I understand what meant: 80% of mutual funds perform below average (the index), hedge fund and individual investors are not doing better. So in other words, being average is actually in the top 20% 🙂

iPhone app

Some tips when creating WCF web service for iPad consumption

Post author By stlplace
Post date October 6, 2012
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Continuation of previous post.

1) WCF get does not like “NULL” column in the query results

2) // note the “id” should match in declaration and method

Tags iOS, Net, wcf, web service

iPhone app

Creating WCF web service II

Post author By stlplace
Post date October 4, 2012
1 Comment on Creating WCF web service II

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A continuation of previous post.

1) Visual Studio, publish web service: check destination IIS app
Before the change, the error was “cannot show the content of the folder”.

2) Add this line to the service.cs (service class C# file), to work around/avoid a problem, asp .net compatibility issue. Do something like this:

[ServiceBehavior]
[AspNetCompatibilityRequirements(RequirementsMode=
AspNetCompatibilityRequirementsMode.Allowed)]
class BarService : IHelloContract
{
// …
}

Refer to wenlong

3) Bad request: it appears to be a class rename problem, Visual Studio has a “red” warning sign, follow it and accept “update”, rebuild.

Tags Net, wcf, web service

iPhone app

Two mac tips

Reading Time: < 1 minute

1) This puzzelled me for a while, my macbook air run out of space often. I was trying to use the build “Finder” to find large files, delete files and some unused apps, to no avail. I did some more google and used this Mac App “FindSpace”. And I found this directory /var/vm has some large swap files. Aha. Found the culprit. This article from osxdaily has more explanation.

2) Old Macbook heat. My 3 years old macbook air recently has the problem of overheat. It heated up fairly quickly after using 10 to 15 minutes. Did some google and found this one described my symptom well. The solution appears to be “SMC reset”. I did it yesterday and it works better at least for now…

(01-02-2017) I found chrome can take a lot space too, as well as the iTunes (iPhone) backup file (appears under mobile sync). Also the MacBook Pro retina has similar battery issue (cannot charge), did Smc reset, worked a while. Eventually had to send to Apple Store for a complete fix.

iPhone app

Three way to create customized input control for UITextField

Post author By stlplace
Post date August 9, 2012
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Recently I need to create some customized textfield to input numbers and text on iPad. I don’t like the default keyboard on iPad because it takes too much of the screen, and in some cases covers up the input field.

1) From iphonedevsdk: What is proper way to do UITextField text change call back? (this also mentioned by stackoverflow)

[textField addTarget:self action:@selector(textFieldDidChange:) forControlEvents:UIControlEventTouchDown];

The downside of this approach is: it takes a press (a tap and hold) to trigger the event.

2) InputView
Create a customized view such as this one at raywenderlich, then set the inputView of textfield. I used this approach to create a number pad that used to only input numbers. There is some limit to this approach as well: the location of customized input view is usually fixed, and in my case (a double picker) for text field (table cell), that is not ideal. I was using pop over controller (again raywenderlich), combined with approach 1, the user does not like the “hold”. After I changed to approach 2, the user does not like the fixed location of input view. So I did more research, and eventually I found the following approach that works for me.

One tip: make sure lock the input view, otherwise it will mess up things after iPad rotation.
– (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return NO;
}

3) self delegate, UITextFieldDelegate

Make sure do this in viewDidLoad (or other place initialize the text field):
myTextField.delegate = self;

This way I could have both “single tap” and the pop over controller.

iPhone app

Create .NET WCF Restful web service for iOS

Post author By stlplace
Post date March 13, 2012
6 Comments on Create .NET WCF Restful web service for iOS

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I need to create a .NET web service consumable by iOS device. Did some research and found out WCF Restful service is the way to go. I used the following examples (tutorials) to construct my web service.

0) Basic Resource Service (link here).
This is basically a self hosting web service run in a main program. A good starting point to learn dataContract, webHttp, etc.

1) I need to change from a console app to a web service, and host on IIS, for this refer to
project 1
and
2(Space Service, a WCF web service app)

2) I need to combine 2 services into one program, and I referred to endPoint.tv plural sight podcast “Building RESTfil services with WCF”

The video above mentioned the httputil.js, HTTP POST/PUT utility, which is handy to test “POST” method. Another tool I used to test GET/POST, is “fiddler”.

A Guide to Designing and Building RESTful Web Services with WCF 3.5, also by Aaron Skonnard, Pluralsight

Essentially here we need to design a scheme (end points) for hosting multiple services.

3) Database connection, I used sql client, which is pretty vanilla.

4) Use pretty path instead of port number (routing service, refer to SimpleREST service again)

Also “code project” example
http://www.codeproject.com/Articles/105273/Create-RESTful-WCF-Service-API-Step-By-Step-Guide

Software development

Some Oracle and Java interview questions

Post author By stlplace
Post date November 27, 2011
4 Comments on Some Oracle and Java interview questions

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(Update 02-27-2019) It’s 5 and half years since last update. And two more jobs for me :] Noticed from recent job search in STL, code exercise and code testing (at the spot, pair programming, TDD) is becoming common now in STL, which is unthink of 5.5 years back. I did add a few blog posts on this fronts recently.

Javascript jasmine node.js based testing

Code exercise : linear chamber animation / simulation

Spring, Spring Boot and React

Also, on pure concepts side, Java (J2SE) and J2EE (Spring and Hibernate) are still important and questions were asked around both areas too.

Example questions:
JPA annotations
Hibernate configuration (XML file)
OOP Concepts
Java Interface vs Abstract class (do we need to implement abstract method to use the class)
final finally finalize java
spring model view controller annotation
classpath loading

(Updated 08-31-2013) For those brave hearts venture out the silicon valley/seattle, here is the must-do homework (LeetCode). Chinese version (here and here).

(Original)
Oracle
SQL: Inner join and out join

Function, (stored) procedure and package

What is a trigger in Oracle

“…Oracle lets you define procedures called triggers that run implicitly when an INSERT, UPDATE, or DELETE statement is issued against the associated table or, in some cases, against a view, or when database system actions occur. These procedures can be written in PL/SQL or Java and stored in the database, or they can be written as C callouts.

Triggers are similar to stored procedures. A trigger stored in the database can include SQL and PL/SQL or Java statements to run as a unit and can invoke stored procedures. However, procedures and triggers differ in the way that they are invoked. A procedure is explicitly run by a user, application, or trigger. Triggers are implicitly fired by Oracle when a triggering event occurs, no matter which user is connected or which application is being used…”

A shorter version at orafaq forum

Longer version at orafaq.com/wiki

7. Compare and contrast TRUNCATE and DELETE for a table.
Both the truncate and delete command have the desired outcome of getting rid of all the rows in a table. The difference between the two is that the truncate command is a DDL operation and just moves the high water mark and produces a now rollback. The delete command, on the other hand, is a DML operation, which will produce a rollback and thus take longer to complete.

8. Give the reasoning behind using an index.
Faster access to data blocks in a table.

11. Give some examples of the types of database contraints you may find in Oracle and indicate their purpose.
A Primary or Unique Key can be used to enforce uniqueness on one or more columns.
A Referential Integrity Contraint can be used to enforce a Foreign Key relationship between two tables.
A Not Null constraint – to ensure a value is entered in a column
A Value Constraint – to check a column value against a specific set of values.

DDL vs DML
Data Definition Language (DDL) statements are used to define the database structure or schema. Some examples:
CREATE – to create objects in the database
ALTER – alters the structure of the database
DROP – delete objects from the database
TRUNCATE – remove all records from a table, including all spaces allocated for the records are removed
COMMENT – add comments to the data dictionary
RENAME – rename an object

Data Manipulation Language (DML) statements are used for managing data within schema objects. Some examples:
SELECT – retrieve data from the a database
INSERT – insert data into a table
UPDATE – updates existing data within a table
DELETE – deletes all records from a table, the space for the records remain
MERGE – UPSERT operation (insert or update)
CALL – call a PL/SQL or Java subprogram
EXPLAIN PLAN – explain access path to data
LOCK TABLE – control concurrency

1. Describe the difference between a procedure, function and anonymous pl/sql block. Candidate should mention use of DECLARE statement, a function must return a value while a procedure doesn?t have to.

PL/SQL developer vs. Toad

Reporting
SQL Server Reporting Services (Microsoft); SQL Server Reporting Services (wiki)

Oracle 10g reports (PDF); Oracle Reports Tutorial

LIMS (wiki)

Java
(Updated 08-31-2013) OOPS Interview Questions

Top 20 Core Java Interview questions answers asked in Investment Bank

(Original) 30 Core Java questions (sys-con)

J2EE interview questions (techInterviews.com)