- What is DATA.HUD.GOV?
DATA.HUD.GOV was developed by The Office of the Chief Information Officer to provide web service based access to publicly available, machine readable datasets generated by the U.S. Department of Housing and Urban Development.Data.HUD.GOV provides a listing of all available services, information on each, example code and a “Try This API” section so end users will have all information they need to produce meaningful results.
- What is a web service?
Web services (sometimes called application services) are services (usually including some combination of programming and data, but possibly including human resources as well) that are made available from a business's Web server for Web users or other Web-connected programs. Providers of Web services are generally known as application service providers.
Source: http://searchsoa.techtarget.com/definition/Web-services
- Who can use the web services on DATA.HUD.GOV?
Anyone. DATA.HUD.GOV was created with the idea that anyone (students, researchers, third party developers, etc.) could learn about HUD’s public facing web services and utilize them to create meaningful output.
- How to access the web services on DATA.HUD.GOV?
Currently, DATA.HUD.GOV only provides RESTful web services, so accessing these services are simple. An end user to these services would only need to use the “Try This API” section of each service to have live data returned to them. One could also user any modern web browser and the API URL to have data returned in their browser.
Alternatively, an end user could create a program to access these web services and process the results.
Example: To get a list of all “Services” that are used in the Housing Counseling web service, you could use the following URL in your web browser to see results. http://data.hud.gov/Housing_Counselor/getServices
- What is a RESTful web service?
REST (REpresentational State Transfer) is a simple stateless architecture that generally runs over HTTP/HTTPS.
As described in a dissertation by Roy Fielding, REST is an "architectural style" that basically exploits the existing technology and protocols of the Web, including HTTP (Hypertext Transfer Protocol), XML, and JSON. REST is simpler to use than the well-known SOAP (Simple Object Access Protocol) approach, which requires writing or using a provided server program (to serve data) and a client program (to request data).
Source: http://searchsoa.techtarget.com/definition/REST
- What is SOAP?
SOAP, originally defined as Simple Object Access Protocol, is a protocol specification for exchanging structured information in the implementation of Web Services in computer networks. It relies on XML Information Set for its message format, and usually relies on other Application Layer protocols, most notably Hypertext Transfer Protocol (HTTP), for message negotiation and transmission.
DATA.HUD.GOV does not currently provide any SOAP services.
Source: http://en.wikipedia.org/wiki/SOAP
- Do you have sample code for accessing the web services on DATA.HUD.GOV?
Each web service provided on DATA.HUD.GOV has a detail page that contains a section that provides a sample JavaScript/JQuery function that will fetch and process the results.
Other languages can be used to access these web services, but examples are not provided on this site.
- How can I test the web services on DATA.HUD.GOV?
Developers can use the sample code provided on each web service page, or create their own project, and compare the results returned by their system to the results displayed in the “Try This API” section for each service.
- What is a query string?
A query string is the part of a URL that contains data to be passed to web applications like the web services provided on DATA.HUD.GOV.
Example: http://data.hud.gov/Housing_Counselor/search?AgencyName=&City=&State=DC&RowLimit=&Services=&Languages=
Source: http://en.wikipedia.org/wiki/Query_string
- What is XML?
Extensible Markup Language (XML) is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable.
Currently, DATA.HUD.GOV does not provide any services that return an XML result.
Source: http://en.wikipedia.org/wiki/XML
- What is a JSON object?
JSON stands for JavaScript Object Notation and is a lightweight text-data interchange format that is language independent and similar to XML but smaller and faster to parse.
Many different libraries exist for various programming languages to create and parse JSON objects.
Currently, all web services on DATA.HUD.GOV return results in JSON format.
Source: http://www.w3schools.com/json/
- What is the best time for accessing the system for bulk downloads?
The services on DATA.HUD.GOV are not designed to deliver all data to end users. If you need access to the full datasets, please contact HUD at
OpenData@hud.gov- Are there any authentication or security mechanisms that I will need to implement to access the web services on DATA.HUD.GOV?
No. All services on DATA.HUD.GOV are open to the public and do not require any authentication at this time. App Tokens are only used on an as needed basis. HUD does reserve the right to change access policies on DATA.HUD.GOV at any time.
- What are App Tokens?
App Tokens are keys used to identify which organizations and applications are accessing resources on DATA.HUD.GOV.
- Will I need an App Token to access web services on DATA.HUD.GOV?
Not at this time. App Tokens are only used on an as needed basis. HUD does reserve the right to change access policies on DATA.HUD.GOV at any time.
