Javascript Data Request Form: Difference between revisions
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My goal is to create a Javascript API for accessing OpenDAP metadata and an intuitive, Javascript-based data-request construction form. | My goal is to create a Javascript API for accessing OpenDAP metadata and an intuitive, Javascript-based data-request construction form. | ||
'''Please note:''' This is a proposal for a Google Summer of Code project. It was not implemented. | |||
== Plan of action == | == Plan of action == | ||
# Create | # Create API for accessing geographical and time data with Javascript by modifying existing BES module or adding a new one | ||
## Write | # Create Javascript library for easily accessing OpenDAP metadata | ||
## Write | ## Write asynchronous metadata retrieval interface | ||
## Write metadata parser | |||
## Write JSON emitter | ## Write JSON emitter | ||
# Create data request form constructor using metadata bridge | # Create data request form constructor using metadata bridge | ||
## Write basic form constructor to build simple but clear HTML forms | ## Write basic form constructor to build simple but clear HTML forms | ||
## Add more advanced form controls (maps, timelines, etc.) for more capable browsers | ## Add more advanced form controls (maps, timelines, etc.) for more capable browsers | ||
== Execution path == | |||
# User requests data-request form | |||
# Server sends simple HTML page with form-generation Javascript | |||
# Javascript requests DDS and DAS for selected data | |||
# Javascript parses DDS and DAS to generate HTML form | |||
# User requests data through form | |||
# Server returns user-selected data | |||
== Application structure == | |||
=== Form generator === | |||
==== Public interface ==== | |||
The public interface gives developers a dead-simple interface to create data-specific request forms. | |||
<code><pre> | |||
createDataRequestForm({"url" : "http://test.com/data.gz", "containerID" : "requestform"}); | |||
</pre></code> | |||
==== Generator ==== | |||
The heart of the form generator transforms the JSON-encoded DAS and DDS into an interactive HTML form. | |||
<code><pre> | |||
var generator = createFormGenerator(); | |||
var form = generator.generateForm(dasData, ddsData); | |||
document.appendChild(form); | |||
</pre></code> | |||
=== DAS/DDS Javascript API === | |||
==== Public interface ==== | |||
The public interface allows developers to easily fetch JSON-encoded DAS and DDS data from a data source. | |||
<code><pre> | |||
var dasData = fetchDAS("http://test.com/data.gz"); | |||
var ddsData = fetchDDS("http://test.com/data.gz"); | |||
</pre></code> | |||
==== HTTP request generator ==== | |||
This critical piece will handle fetching the raw DAS or DDS data from the server. | |||
<code><pre> | |||
var rawDASData = fetch({"url" : "http://test.com/data.gz.das", "callback" : onDataReceived}); | |||
</pre></code> | |||
==== DAS parser ==== | |||
The DAS parser will convert the raw DAS data into a Javascript-accessible JSON object. | |||
<code><pre> | |||
var dasParser = createDASParser(); | |||
var dasData = dasParser.parse(rawDASData); | |||
</pre></code> | |||
==== DDS parser ==== | |||
Like the DAS parser, the DDS parser will translate a raw DDS string into a JSON object. | |||
<code><pre> | |||
var ddsParser = createDDSParser(); | |||
var ddsData = ddsParser.parse(rawDDSData); | |||
</pre></code> |
Latest revision as of 18:45, 12 February 2016
My goal is to create a Javascript API for accessing OpenDAP metadata and an intuitive, Javascript-based data-request construction form.
Please note: This is a proposal for a Google Summer of Code project. It was not implemented.
Plan of action
- Create API for accessing geographical and time data with Javascript by modifying existing BES module or adding a new one
- Create Javascript library for easily accessing OpenDAP metadata
- Write asynchronous metadata retrieval interface
- Write metadata parser
- Write JSON emitter
- Create data request form constructor using metadata bridge
- Write basic form constructor to build simple but clear HTML forms
- Add more advanced form controls (maps, timelines, etc.) for more capable browsers
Execution path
- User requests data-request form
- Server sends simple HTML page with form-generation Javascript
- Javascript requests DDS and DAS for selected data
- Javascript parses DDS and DAS to generate HTML form
- User requests data through form
- Server returns user-selected data
Application structure
Form generator
Public interface
The public interface gives developers a dead-simple interface to create data-specific request forms.
createDataRequestForm({"url" : "http://test.com/data.gz", "containerID" : "requestform"});
Generator
The heart of the form generator transforms the JSON-encoded DAS and DDS into an interactive HTML form.
var generator = createFormGenerator();
var form = generator.generateForm(dasData, ddsData);
document.appendChild(form);
DAS/DDS Javascript API
Public interface
The public interface allows developers to easily fetch JSON-encoded DAS and DDS data from a data source.
var dasData = fetchDAS("http://test.com/data.gz");
var ddsData = fetchDDS("http://test.com/data.gz");
HTTP request generator
This critical piece will handle fetching the raw DAS or DDS data from the server.
var rawDASData = fetch({"url" : "http://test.com/data.gz.das", "callback" : onDataReceived});
DAS parser
The DAS parser will convert the raw DAS data into a Javascript-accessible JSON object.
var dasParser = createDASParser();
var dasData = dasParser.parse(rawDASData);
DDS parser
Like the DAS parser, the DDS parser will translate a raw DDS string into a JSON object.
var ddsParser = createDDSParser();
var ddsData = ddsParser.parse(rawDDSData);