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• How do I avoid spam domains pointing to my site or IP

  - by Amol Ghotankar

  I came across an issue where I saw some xyz.com is pointing to mydomain.com. How do I avoid spam domains pointing to my domain? I read some posts about setting my virtual hosts and such, but nothing specific about how to avoid it in the first place. I searched on Google but most answers are for HTTP servers and there are no exact answers for Tomcat 7. I am not using Apache or IIS, but Tomcat directly.

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• Unit Testing with NUnit and Moles Redux

  - by João Angelo

  Almost two years ago, when Moles was still being packaged alongside Pex, I wrote a post on how to run NUnit tests supporting moled types. A lot has changed since then and Moles is now being distributed independently of Pex, but maintaining support for integration with NUnit and other testing frameworks. For NUnit the support is provided by an addin class library (Microsoft.Moles.NUnit.dll) that you need to reference in your test project so that you can decorate yours tests with the MoledAttribute. The addin DLL must also be placed in the addins folder inside the NUnit installation directory. There is however a downside, since Moles and NUnit follow a different release cycle and the addin DLL must be built against a specific NUnit version, you may find that the release included with the latest version of Moles does not work with your version of NUnit. Fortunately the code for building the NUnit addin is supplied in the archive (moles.samples.zip) that you can found in the Documentation folder inside the Moles installation directory. By rebuilding the addin against your specific version of NUnit you are able to support any version. Also to note that in Moles 0.94.51023.0 the addin code did not support the use of TestCaseAttribute in your moled tests. However, if you need this support, you need to make just a couple of changes. Change the ITestDecorator.Decorate method in the MolesAddin class: Test ITestDecorator.Decorate(Test test, MemberInfo member) { SafeDebug.AssumeNotNull(test, "test"); SafeDebug.AssumeNotNull(member, "member"); bool isTestFixture = true; isTestFixture &= test.IsSuite; isTestFixture &= test.FixtureType != null; bool hasMoledAttribute = true; hasMoledAttribute &= !SafeArray.IsNullOrEmpty( member.GetCustomAttributes(typeof(MoledAttribute), false)); if (!isTestFixture && hasMoledAttribute) { return new MoledTest(test); } return test; } Change the Tests property in the MoledTest class: public override System.Collections.IList Tests { get { if (this.test.Tests == null) { return null; } var moled = new List<Test>(this.test.Tests.Count); foreach (var test in this.test.Tests) { moled.Add(new MoledTest((Test)test)); } return moled; } } Disclaimer: I only tested this implementation against NUnit 2.5.10.11092 version. Finally you just need to run the NUnit console runner through the Moles runner. A quick example follows: moles.runner.exe [Tests.dll] /r:nunit-console.exe /x86 /args:[NUnitArgument1] /args:[NUnitArgument2]

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• Software for Managing Subscriptions to Website Content?

  - by an00b

  Can you recommend a package that allows me to manage subscriptions to certain content on my website (not necessarily displayable) based on payment levels? Ideally, the software would allow logging in using both site-specific registration and PayPal/Facebook/Twitter/MyOpenId, etc. Preferably, it would also be open source, LAMP-based. One idea that I have in mind is hacking a shopping cart software like Zen-Cart but this may be an overkill if a non-shopping lighter-weight package exists.

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• Is Google a reliable document search engine?

  - by Miriam Schwab

  I have a site with PDFs and Word documents that I know have been indexed by Google because they appear in search results with filetype:pdf (or doc), and if I search for some very specific terms with quotation marks, they appear as well. But they don't appear for general search terms that do exist in the documents. Is Google a reliable document search engine? If not, are there other options for managing many documents and making them searchable to users?

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• How can I prevent spam on sites which I control?

  - by danlefree

  This is a general, community wiki question to address all non-specific spam prevention questions. If your question was closed as a duplicate of this question and you feel that the information provided here does not provide a sufficient answer, please open a discussion on Pro Webmasters Meta. For purposes of this question, spam will include: Any automated post Manually-posted content which includes links to spammers' sites Manually-posted content which includes instructions to visit a spammer's site

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• Chargeback and showback...both a 'throw back'

  - by llaszews

  Been getting asked again by customers and partners about chargeback and showback in the cloud so thought I would blog on my response to this question. Charge Back background, information and industry analysis: Cloud computing is all about shared resources. These shared resources are computer servers (including memory and CPU), network devices, hard disk storage, database servers, application servers, cooling, floor space, electricity and more. These resources are shared by departments within a company, or by a number of companies, when resources are hosted in the public or hybrid cloud. Currently, hosting providers that run other companies on their cloud platforms do not have an accurate way to measure the shared computing resources used by a specific user let alone used by a specific customer. Additionally, companies running their own cloud data centers, for private or hybrid clouds, have no way of measure and charging back the departments in the company that are using these shared cloud resources. In both cases, the lack of determine shared resource costs and to charge them back to the company, department or user that is using this resources is limited a clear measure of business benefit and impacting company’s ability to measure the Return on Investment (ROI). An IT chargeback system is an accounting strategy that applies the costs of IT services, hardware or software to the business unit in which they are used. This system contrasts with traditional IT accounting models in which a centralized department bears all of the IT costs in an organization and those costs are treated simply as corporate overhead. Showback involves showing the IT costs to a department or customer but not actually charging them for their IT usage. Showback is a gradual method of introducing chargeback into an enterprise. Most companies implement a show back mechanism before a full chargeback system is put in place. Oracle chargeback product: Oracle Enterprise Manager provides tools for defining detailed Chargeback plans spanning different metrics collected for each type of resources as well as defining Cost Centers for grouping costs across multiple developers. Chargeback plans can use not only usage based costs, but also configuration based costs (e.g. version of the platform) or fixed costs (e.g. flat-rate management fee). Chargeback has rich out of the box reports. Trending reports show how charge and resource consumption varies over time, while Summary reports show the breakdown of charges or usage by different dimensions such as Cost Center or Target Type. These reports help consumers in understanding how their charges relate to their consumption and also assist the IT department with budgeting and planning activities. With BI Publisher, the reports can be made available in a variety of formats such as PDF, HTML, Word, Excel or PowerPoint.

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• Common Areas For Securing Web Services

  The only way to truly keep a web service secure is to host it on a web server and then turn off the server. In real life no web service is 100% secure but there are methodologies for increasing the security around web services. In order for consumers of a web service they must adhere to the service’s Service-Level Agreement (SLA).  An SLA is a digital contract between a web service and its consumer. This contract defines what methods and protocols must be used to access the web service along with the defined data formats for sending and receiving data through the service. If either part does not abide by the contract then the service will not be accessible for consumption. Common areas for securing web services: Universal Discovery Description Integration  (UDDI) Web Service Description Language  (WSDL) Application Level Network Level “UDDI is a specification for maintaining standardized directories of information about web services, recording their capabilities, location and requirements in a universally recognized format.” (UDDI, 2010) WSDL on the other hand is a standardized format for defining a web service. A WSDL describes the allowable methods for accessing the web service along with what operations it performs. Web services in the Application Level can control access to what data is available by implementing its own security through various methodologies but the most common method is to have a consumer pass in a token along with a system identifier so that they system can validate the users access to any data or actions that they may be requesting. Security restrictions can also be applied to the host web server of the service by restricting access to the site by IP address or login credentials. Furthermore, companies can also block access to a service by using firewall rules and only allowing access to specific services on certain ports coming from specific IP addresses. This last methodology may require consumers to obtain a static IP address and then register it with the web service host so that they will be provide access to the information they wish to obtain. It is important to note that these areas can be secured in any combination based on the security level tolerance dictated by the publisher of the web service. This being said, the bare minimum security implantation must be in the Application Level within the web service itself. Typically I create a security layer within a web services exposed Internet that requires a consumer identifier and a consumer token. This information is then used to authenticate the requesting consumer before the actual request is performed. Refernece:UDDI. (2010). Retrieved 11 13, 2011, from LooselyCoupled.com: http://www.looselycoupled.com/glossary/UDDIService-Level Agreement (SLA). (n.d.). Retrieved 11 13, 2011, from SearchITChannel: http://searchitchannel.techtarget.com/definition/service-level-agreement

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• Empty tooltips in MATLAB

  - by GriffinPeterson

  I am running MATLAB R2013b. Under Unity, the built-in editor of MATLAB shows empty tooltips, as seen here: http://imgur.com/4VSq6i8 Under xfce the tooltips are showing up just fine. My system: Ubuntu 14.04, Intel i7 4770K. The question has already been posted somewhere else (http://stackoverflow.com/questions/21915939/matlab-code-analyzer-produces-empty-tooltips, http://www.mathworks.com/matlabcentral/answers/116987-empty-tooltips-in-code-analyzer ), but I think this is a Unity-specific problem. Any ideas?

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• Reading A User's Profile

  - by Ricardo Peres

  One frequent question is: how can we read a user's profile properties? The answer is simple, we use class ProfileBase: //a specific user ProfileBase profile = ProfileBase.Create("username", true); //all users BaseProfile [] profiles = Membership.GetAllUsers().Cast().Select(u = ProfileBase.Create(u.UserName, true)).ToArray(); SyntaxHighlighter.config.clipboardSwf = 'http://alexgorbatchev.com/pub/sh/2.0.320/scripts/clipboard.swf'; SyntaxHighlighter.brushes.CSharp.aliases = ['c#', 'c-sharp', 'csharp']; SyntaxHighlighter.all();

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• Has any hobbyist attempted to make a simple VGA-graphics based operating system in machine code?

  - by Bigyellow Bastion

  I mean real bare bones, bare machine here(no Linux kernel, pre-existing kernel, or any bootloader). I mean honestly write the bootloading software in direct microarchitecture-specific machine opcode, host the operating system, interrupts, I/O, services, and graphical software and all hardware interaction, computation, and design entirely in binary. I know this is quite the leap here, but I was thinking to practice first in x86 assembly (not binary) 16-bit style. Any ideas?

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• Different Directives for Dot NET

  Directives are those that are responsible for any kind of change in the settings that decide the actions of an entire page. They are language specific and for .NET they function as settings of the pa... [Author: Jessica Woodson - Web Design and Development - April 10, 2010]

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• Files and content search outside from opened Visual Studio solution

  - by Suresh Behera

  I have been using Visual studio for decade now and never notice a useful search option on “Find and Replace”  wizard.One of my client still use Windows XP for their development machine.We have set of projects separated to specific group or solutions. So,i always have challenge to find some contents or files other than current opened solutions.On windows 7 it is easier go folder and look for content but not so easy on windows XP.Following “Find and Replace” and content search found very helpful...(read more)

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• Can anybody recommend C#/XAML Windows Store Development aggregator sites?

  - by Clay Shannon

  I used to have a couple of sites bookmarked that were Windows development article/blog post aggregators. I can't recall what they were called. What I want to do now is to keep up with all relevant C#/XAML "Windows Store" app development info, whether it be blog posts, new "Metro"-specific channel 9 videos, etc., without spending lots of time surfing about. Can anybody recommend any "C#/XAML Windows Store new information aggregators"?

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• New Oracles VM RAC template with support for oracle vm 3 built-in

  - by wcoekaer

  The RAC team did it again (thanks Saar!) - another awesome set of Oracle VM templates published and uploaded to My Oracle Support. You can find the main page here. What's special about the latest version of DeployCluster is that it integrates tightly with Oracle VM 3 manager. It basically is an Oracle VM frontend that helps start VMs, pass arguments down automatically and there is absolutely no need to log into the Oracle VM servers or the guests. Once it completes, you have an entire Oracle RAC database setup ready to go. Here's a short summary of the steps : Set up an Oracle VM 3 server pool Download the Oracle VM RAC template from oracle.com Import the template into Oracle VM using Oracle VM Manager repository - import Create a public and private network in Oracle VM Manager in the network tab Configure the template with the right public and private virtual networks Create a set of shared disks (physical or virtual) to assign to the VMs you want to create (for ASM/at least 5) Clone a set of VMs from the template (as many RAC nodes as you plan to configure) With Oracle VM 3.1 you can clone with a number so one clone command for, say 8 VMs is easy. Assign the shared devices/disks to the cloned VMs Create a netconfig.ini file on your manager node or a client where you plan to run DeployCluster This little text file just contains the IP addresses, hostnames etc for your cluster. It is a very simple small textfile. Run deploycluster.py with the VM names as argument Done. At this point, the tool will connect to Oracle VM Manager, start the VMs and configure each one, Configure the OS (Oracle Linux) Configure the disks with ASM Configure the clusterware (CRS) Configure ASM Create database instances on each node. Now you are ready to log in, and use your x node database cluster. x No need to download various products from various websites, click on trial licenses for the OS, go to a Virtual Machine store with sample and test versions only - this is production ready and supported. Software. Complete. example netconfig.ini : # Node specific information NODE1=racnode1 NODE1VIP=racnode1-vip NODE1PRIV=racnode1-priv NODE1IP=192.168.1.2 NODE1VIPIP=192.168.1.22 NODE1PRIVIP=10.0.0.22 NODE2=racnode2 NODE2VIP=racnode2-vip NODE2PRIV=racnode2-priv NODE2IP=192.168.1.3 NODE2VIPIP=192.168.1.23 NODE2PRIVIP=10.0.0.23 # Common data PUBADAP=eth0 PUBMASK=255.255.255.0 PUBGW=192.168.1.1 PRIVADAP=eth1 PRIVMASK=255.255.255.0 RACCLUSTERNAME=raccluster DOMAINNAME=mydomain.com DNSIP= # Device used to transfer network information to second node # in interview mode NETCONFIG_DEV=/dev/xvdc # 11gR2 specific data SCANNAME=racnode12-scan SCANIP=192.168.1.50

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• Solita Oy Achieves Oracle PartnerNetwork Specialization

  - by michaela.seika(at)oracle.com

  Helsinki, February 2, 2011 - Solita Oy, a member of the Oracle® PartnerNetwork (OPN), is the first Finnish enterprise to achieve OPN Specialized status for customer-specific systems integration and software solutions.To achieve a Specialized status, Oracle partners are required to meet a stringent set of requirements that are based on the needs and priorities of the customer and partner community. By achieving a Specialized distinction, Solita Oy has been recognized by Oracle for its expertise in customer-specific systems integration and software solutions, achieved through competency development and demonstrated by the company's business results and proven success in implementing customer projects. "Solita and Oracle have cooperated for a long time, and we have been an Oracle partner for many years. We believe that the renewed partner program and the new partnership level that we have achieved will open up new opportunities for a closer collaboration with Oracle. Our increased focus on systems integration solutions and the stepping up of our specialized knowledge of SOA will enable us to provide even better solutions for our customers," said Jari Niska, Chief Executive Officer, Solita Oy. "Solita has shown trust and belief in Oracle's technology and in the business opportunities arising with it. They have contributed to building our cooperation in a consistent and systematic way. Achieving a Specialized status in our partner program is a natural further step in our close and committed cooperation. It strengthens our trust in our ability to be able to increase both turnover and profitability together," said Juha Kaskirinne, Alliances and Channel Leader, Oracle Finland Oy.  About Oracle PartnerNetwork Oracle PartnerNetwork (OPN) Specialized is the latest version of Oracle's partner program that provides partners with tools to better develop, sell and implement Oracle solutions. OPN Specialized offers resources to train and support specialized knowledge of Oracle products and solutions and has evolved to recognize Oracle's growing product portfolio, partner base and business opportunity. Key to the latest enhancements to OPN is the ability for partners to differentiate through Specializations. Specializations are achieved through competency development, business results, expertise and proven success. To find out more visit http://www.oracle.com/partners or connect with the Oracle Partner community at OPN on Twitter, OPN on Facebook, OPN on LinkedIn, and OPN on YouTube. About Solita Oy Solita Oy is a Finnish company dedicated to developing demanding information system solutions and IT professional services. Solita's customers include prominent Finnish companies and public organizations. Solita's turnover in 2010 was about 17 million euros. The company was founded in 1996 and has over 170 employees. Further information: www.solita.fiFurther information Jari Niska, CEO, Solita Oy, tel. +358 40 524 6400, [email protected] Kaskirinne, A&C Leader Finland, Oracle Finland Oy, tel. +358 40 506 3592, [email protected]

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• What is Advanced Search Operators?

  Search engines have set up further tools referred to as advanced search operators to provide power users possibly far more control when searching. Advanced search operators are distinctive phrases which you could insert in your search query for you to come across unique sorts of details of which the common search are not able to offer. A number of of those operators provide beneficial resources for Search engines gurus and other people who want really special data, or perhaps who wish to minimize their particular search to very specific source.

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• Naming conventions for language file keys

  - by VirtuosiMedia

  What is your strategy for naming conventions for the keys in language files used for localization? We have a team that is going to conversion of a project to multiple languages and would like to have some guidelines to follow. As an example, usually the files end up being a series of key/value pairs, with the key being the placeholder in the template for the language specific value. 'Username': 'Username', 'Enter Username': 'Enter your username here'

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• Principles of an extensible data proxy

  - by Wesley

  There is a growing industry now with more than 30 companies playing in the Backend-As-A-Service (BaaS) market. The principle is simple: give companies a secure way of exposing data housed on premises and behind the firewall publicly. This can include database data, as well as Legacy PC data through established connectors; SAP for example provides a connector for transacting with their legacy systems. Early attempts were fixed providers for specific systems like SAP, IBM or Oracle, but the new breed is extensible, allowing Channel Partners and Consultants to build robust integration applications that can consume whatever data sources the client wants to expose. I just happen to be close to finishing a Cloud Based HTML5 application platform that provides robust integration services, and I would like to break ground on an extensible data proxy to complete the system. From what I can gather, I need to provide either an installable web service of some kind, or a Cloud service which the client can configure with VPN for interactions. Then I can build in connectors, which can be activated with a service account, and expose those transactions via web services of some kind (JSON, SOAP, etc). I can also provide a framework that allows people to build in their own connectors, and use some kind of schema to hook those connectors into the proxy. The end result is some kind of public facing web service that could securely be consumed by applications to show data through HTML5 on any device. My gut is, this isn't as hard as it sounds. Almost all of the 30+ companies (With more popping up almost weekly) have all come into existence in the last 18 months or so, which tells me either the root technology, or the skillset to create the technology is in abundance right now. Where should I start on this? Are there some open source projects I can leverage? A specific group of developers I can hire? I'm confident someone here can set me on the right path and save me some time. You don't see this many companies spring up this rapidly if they are all starting from scratch with proprietary technology. The Register: WTF is BaaS One Minute Video from Kony on their BaaS

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• Where Are You on the Visualization Maturity Curve?

  - by Celine Beck

  The old phrase “A picture is worth a thousand words” is as true now as ever. Providing the right users with access to the right product data, at the right time, can provide significant benefits to a business. This is especially evident with increasing technical and product complexities, elongated supply chains, and growing pressure to bring innovative products to market faster. With this in mind, it is easy to understand why visualization is an integral part of any successful product lifecycle management (PLM) strategy. At a bare minimum, knowledge workers use multiple individual documents of different formats and structure, and leverage visualization solutions to access information; but the real value of visualization can be fully reaped when it is connected to enterprise applications like PLM and tied to the appropriate business context. The picture below illustrates this visualization maturity curve, as we presented during the last Oracle Open World and the transformational effect that visualization can have on PLM processes and performance (check out the post about AutoVue Key Highlights from Oracle Open World 2012 for more information). Organizations are likely to see greater positive impact on business performance when visualization is connected to enterprise systems, allowing access to information coming from multiple sources, such as PLM, supply chain management (SCM) and enterprise resource planning (ERP). This allows organizations to reach higher levels of collaboration and optimize decision-making capacity as users can benefit from in-context access to visual information. For instance, within a PLM system, a design engineer can access a product assembly and review digital annotations added by other users specific to the engineering change request he is reviewing rather than all historical annotations. The last stage on the curve is what we call augmented business visualization (ABV).  ABV is an innovative framework which lets structured data (from Oracle’s Agile PLM for instance) interact with unstructured data (documents, design, 3D models, etc). With this new level of integration, information coming from multiple sources can be presented in a highly visual fashion; color displays can be used in order to identify parts with specific characteristics (for example pending quality issues) and you can take actions directly from within the context of documents and designs, maximizing user productivity. Those who had the chance to attend our PLM session during Oracle Open World already got a sneak peek of our latest augmented business visualization for Oracle’s Agile PLM. The solution generated a lot of wows. Stephen Porter, CEO at Zero Wait State, indicated in a post entitled “The PLM State: the Manhattan Project-Oracle’s Next Big Secret Weapon” that “this kind of synergy between visualization and PLM could qualify as a powerful weapon differentiating Agile PLM from other solutions.” If you are interested in learning more about ABV for Oracle’s Agile PLM and hear about real examples of usage of visualization at all stages of the visualization maturity curve, don’t miss our Visual Decision Making to Optimize New Product Development and Introduction session during the Oracle Value Chain Summit (Feb. 4-6, 2013, San Francisco). We look forward to seeing you there!

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• Search Engine Optimization - The Death of SEO

  In the past it was very easy to optimize a website. All you had to do is create a strong title, write up a keyword rich description and throw in a few industry specific keywords to get your site to rank on the first page of Google, Yahoo, MSN (now Bing), etc.

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• ASP.NET Web Roles vs ASP.NET Web Applications

  - by kaleidoscope

  The 3 differences are: References to the Windows Azure specific assemblies: Microsoft.WindowsAzure.Diagnostics, Microsoft.WindowsAzure.ServiceRuntime, and Microsoft.WindowsAzure.StorageClient Bootstrap code in the WebRole.cs/vb file that starts the DiagnosticMonitor as well as defines a default behavior of recycling the role when a configuration setting change occurs. The addition of a trace listener in the web.config file: Microsoft.WindowsAzure.Diagnostics.DiagnosticMonitorTraceListener.   Amit

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• Instruction vs data cache usage

  - by Nick Rosencrantz

  Say I've got a cache memory where instruction and data have different cache memories ("Harvard architecture"). Which cache, instruction or data, is used most often? I mean "most often" as in time, not amount of data since data memory might be used "more" in terms of amount of data while instruction cache might be used "more often" especially depending on the program. Are there different answers a) in general and b) for a specific program?

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• is Microsoft LC random generator patented?

  - by user396672

  I need a very simple pseudo random generator (no any specific quality requirements) and I found Microsoft's variant of LCG algorithm used for rand() C runtime library function fit my needs (gcc's one seems too complex). I found the algorithm here: http://rosettacode.org/wiki/Linear_congruential_generator#C However, I worry the algorithm (including its "magic numbers" i.e coefficients) may by patented or restricted for use in some another way. Is it allowed to use this algorithm without any licence or patent restrictions or not? I can't use library rand() because I need my results to be exactly reproducible on different platforms

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• SEO best practices for a web feature that uses geolocation by IP Address

  - by Nick

  I'm working on a feature that tailors content based on a geo location lookup by IP address in order to provide information based on the general area where this visitor is from. I'm concerned that content will be interpreted as focused solely on the search engine spider's geo origin when it is indexed. Are there SEO best practices for geo location by ip address features? I appreciate any specific tips or words of wisdom.

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• Why do we (really) program to interfaces?

  - by Kyle Burns

  One of the earliest lessons I was taught in Enterprise development was "always program against an interface".  This was back in the VB6 days and I quickly learned that no code would be allowed to move to the QA server unless my business objects and data access objects each are defined as an interface and have a matching implementation class.  Why?  "It's more reusable" was one answer.  "It doesn't tie you to a specific implementation" a slightly more knowing answer.  And let's not forget the discussion ending "it's a standard".  The problem with these responses was that senior people didn't really understand the reason we were doing the things we were doing and because of that, we were entirely unable to realize the intent behind the practice - we simply used interfaces and had a bunch of extra code to maintain to show for it. It wasn't until a few years later that I finally heard the term "Inversion of Control".  Simply put, "Inversion of Control" takes the creation of objects that used to be within the control (and therefore a responsibility of) of your component and moves it to some outside force.  For example, consider the following code which follows the old "always program against an interface" rule in the manner of many corporate development shops: 1: ICatalog catalog = new Catalog(); 2: Category[] categories = catalog.GetCategories(); In this example, I met the requirement of the rule by declaring the variable as ICatalog, but I didn't hit "it doesn't tie you to a specific implementation" because I explicitly created an instance of the concrete Catalog object.  If I want to test the functionality of the code I just wrote I have to have an environment in which Catalog can be created along with any of the resources upon which it depends (e.g. configuration files, database connections, etc) in order to test my functionality.  That's a lot of setup work and one of the things that I think ultimately discourages real buy-in of unit testing in many development shops. So how do I test my code without needing Catalog to work?  A very primitive approach I've seen is to change the line the instantiates catalog to read: 1: ICatalog catalog = new FakeCatalog();   once the test is run and passes, the code is switched back to the real thing.  This obviously poses a huge risk for introducing test code into production and in my opinion is worse than just keeping the dependency and its associated setup work.  Another popular approach is to make use of Factory methods which use an object whose "job" is to know how to obtain a valid instance of the object.  Using this approach, the code may look something like this: 1: ICatalog catalog = CatalogFactory.GetCatalog();   The code inside the factory is responsible for deciding "what kind" of catalog is needed.  This is a far better approach than the previous one, but it does make projects grow considerably because now in addition to the interface, the real implementation, and the fake implementation(s) for testing you have added a minimum of one factory (or at least a factory method) for each of your interfaces.  Once again, developers say "that's too complicated and has me writing a bunch of useless code" and quietly slip back into just creating a new Catalog and chalking any test failures up to "it will probably work on the server". This is where software intended specifically to facilitate Inversion of Control comes into play.  There are many libraries that take on the Inversion of Control responsibilities in .Net and most of them have many pros and cons.  From this point forward I'll discuss concepts from the standpoint of the Unity framework produced by Microsoft's Patterns and Practices team.  I'm primarily focusing on this library because it questions about it inspired this posting. At Unity's core and that of most any IoC framework is a catalog or registry of components.  This registry can be configured either through code or using the application's configuration file and in the most simple terms says "interface X maps to concrete implementation Y".  It can get much more complicated, but I want to keep things at the "what does it do" level instead of "how does it do it".  The object that exposes most of the Unity functionality is the UnityContainer.  This object exposes methods to configure the catalog as well as the Resolve<T> method which is used to obtain an instance of the type represented by T.  When using the Resolve<T> method, Unity does not necessarily have to just "new up" the requested object, but also can track dependencies of that object and ensure that the entire dependency chain is satisfied. There are three basic ways that I have seen Unity used within projects.  Those are through classes directly using the Unity container, classes requiring injection of dependencies, and classes making use of the Service Locator pattern. The first usage of Unity is when classes are aware of the Unity container and directly call its Resolve method whenever they need the services advertised by an interface.  The up side of this approach is that IoC is utilized, but the down side is that every class has to be aware that Unity is being used and tied directly to that implementation. Many developers don't like the idea of as close a tie to specific IoC implementation as is represented by using Unity within all of your classes and for the most part I agree that this isn't a good idea.  As an alternative, classes can be designed for Dependency Injection.  Dependency Injection is where a force outside the class itself manipulates the object to provide implementations of the interfaces that the class needs to interact with the outside world.  This is typically done either through constructor injection where the object has a constructor that accepts an instance of each interface it requires or through property setters accepting the service providers.  When using dependency, I lean toward the use of constructor injection because I view the constructor as being a much better way to "discover" what is required for the instance to be ready for use.  During resolution, Unity looks for an injection constructor and will attempt to resolve instances of each interface required by the constructor, throwing an exception of unable to meet the advertised needs of the class.  The up side of this approach is that the needs of the class are very clearly advertised and the class is unaware of which IoC container (if any) is being used.  The down side of this approach is that you're required to maintain the objects passed to the constructor as instance variables throughout the life of your object and that objects which coordinate with many external services require a lot of additional constructor arguments (this gets ugly and may indicate a need for refactoring). The final way that I've seen and used Unity is to make use of the ServiceLocator pattern, of which the Patterns and Practices team has also provided a Unity-compatible implementation.  When using the ServiceLocator, your class calls ServiceLocator.Retrieve in places where it would have called Resolve on the Unity container.  Like using Unity directly, it does tie you directly to the ServiceLocator implementation and makes your code aware that dependency injection is taking place, but it does have the up side of giving you the freedom to swap out the underlying IoC container if necessary.  I'm not hugely concerned with hiding IoC entirely from the class (I view this as a "nice to have"), so the single biggest problem that I see with the ServiceLocator approach is that it provides no way to proactively advertise needs in the way that constructor injection does, allowing more opportunity for difficult to track runtime errors. This blog entry has not been intended in any way to be a definitive work on IoC, but rather as something to spur thought about why we program to interfaces and some ways to reach the intended value of the practice instead of having it just complicate your code.  I hope that it helps somebody begin or continue a journey away from being a "Cargo Cult Programmer".

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