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From Apache Wiki <wikidi...@apache.org>
Subject [Couchdb Wiki] Update of "Formatting_with_Show_and_List" by SebastianCohnen
Date Thu, 08 Apr 2010 18:34:23 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Couchdb Wiki" for change notification.

The "Formatting_with_Show_and_List" page has been changed by SebastianCohnen.
The comment on this change is: added syntax-hl; added toc; fixed example indentation .
http://wiki.apache.org/couchdb/Formatting_with_Show_and_List?action=diff&rev1=19&rev2=20

--------------------------------------------------

+ <<TableOfContents()>>
+ = Formatting with Show and List =
+ 
  Note that this is only available in CouchDB 0.9 or newer — The API might still change.
  
  The basics of formatting documents using `show` and `list` functions. These functions convert
documents and views, respectively, into non-JSON formats. The rows of each view are processed
individually, which keeps long lists from becoming memory hogs.
@@ -11, +14 @@

  == Showing Documents ==
  Show functions are stored in your design document, under the `shows` key. Here's an example
set of show functions:
  
- {{{
+ {{{#!highlight javascript
  {
- "_id" : "_design/examples",
+     "_id": "_design/examples",
- "shows" : {
+     "shows": {
-   "posts" : "function(doc, req) {... return responseObject;}",
+         "posts": "function(doc, req) { /*...*/ return responseObject;}",
-   "people" : "function(doc, req) { ... }"
+         "people": "function(doc, req) { /*...*/ }"
+     }
  }
  }}}
  Assuming these functions were in a design document named "`examples`" in a database named
"`db`", they could be queried like this:
@@ -32, +36 @@

  
  Example `show` function
  
- {{{
+ {{{#!highlight javascript
  function(doc, req) {
    return {
      body: "Hello World"
@@ -43, +47 @@

  
  If the show function is queried without a document id at all, doc is `null` and `req.docId`
is `null`. This is useful for creating new documents where the user specifies the new document
id in a user interface, like in a CMS.
  
- {{{
+ {{{#!highlight javascript
  function(doc, req) {
    if(doc) {
      // regular doc display logic
@@ -61, +65 @@

  == Listing Views with couchdb 0.9 ==
  List functions are stored under the `lists` key of a design document. Here's an example
design doc with list functions, in addition to views:
  
- {{{
+ {{{#!highlight javascript
  {
- "_id" : "_design/examples",
+     "_id": "_design/examples",
- "views" {
+     "views" {
-   "posts-by-date" : "function(doc){...}",
+         "posts-by-date": "function(doc){ /*...*/ }",
-   "posts-by-tag" : "function(doc){...}",
+         "posts-by-tag": "function(doc){ /*...*/ }",
-   "people-by-name" : "function(doc) {...}"
+         "people-by-name": "function(doc) { /*...*/ }"
- },
+     },
- "lists" : {
+     "lists": {
-   "index-posts" : "function(head, row, req, row_info) {...}",
+         "index-posts": "function(head, row, req, row_info) { /*...*/ }",
-   "browse-people" : "function(head, row, req, row_info) { ... }"
+         "browse-people": "function(head, row, req, row_info) { /*...*/ }"
+     }
  }
  }}}
  These lists are run by querying URLs like:
@@ -83, +88 @@

  
  GET /db/_design/examples/_list/browse-people/people-by-name?startkey=["a"]&limit=10
  }}}
- [As above, we assume the database is named "db" and the design doc "examples".]
+ As above, we assume the database is named "db" and the design doc "examples".
  
  Couchdb 0.10 supports an alternate form of URL which allows you to use a list function and
a view from different design documents.  This is particularly useful when you want to use
a different language for the list and for the view.  These URLs are very similar to the above
examples, but instead of the tail portion being the name of the view, the tail portion can
consist of two parts - a design doc name and the name of the view in that second document.
 For example:
  
@@ -94, +99 @@

  
  A list function has a more interesting signature, as it is passed the head of the view on
first invocation, then each row in turn, then called one more time for the tail of the view.
The function should check the `head` and `row` parameters to identify which state it's being
called in; the sequence of calls to `listfn`, for a view with three rows, would look like:
  
- {{{
+ {{{#!highlight javascript
-   listfn(head, null,    req, null    );  // Before the first row: head is non-null
+ listfn(head, null,    req, null    );  // Before the first row: head is non-null
-   listfn(null, rows[0], req, row_info);  // First row
+ listfn(null, rows[0], req, row_info);  // First row
-   listfn(null, rows[1], req, row_info);  // Subsequent rows...
+ listfn(null, rows[1], req, row_info);  // Subsequent rows...
-   listfn(null, rows[2], req, row_info);
+ listfn(null, rows[2], req, row_info);
-   listfn(null, null,    req, row_info);  // After last row: row=null
+ listfn(null, null,    req, row_info);  // After last row: row=null
  }}}
  The `head` parameter -- which is only passed into the first call -- contains an object with
information about the view that is to be iterated over. It's much like the response object
returned from a view query in the CouchDB JavaScript API; useful properties include `total_rows`
and `offset`.
  
@@ -111, +116 @@

  
  Example list function:
  
- {{{
+ {{{#!highlight javascript
  function(head, row, req, row_info) {
    if (head) {
      return "<p>head: "+JSON.stringify(head)+"</p><ul>";
@@ -122, +127 @@

    }
  }
  }}}
+ 
  == Listing Views with couchdb 0.10 ==
  The list API has changed significantly from 0.9 to 0.10.
  
  Example `list` function
  
- {{{
+ {{{#!highlight javascript
- function(head, req){
+ function(head, req) {
    var row;
    while(row = getRow()) {
      send(row.value);
    }
  }
  }}}
+ 
  == Other Fun Things ==
  === Stopping iteration in a `_list` ===
  If you want to terminate iteration of a `_list` early you can return a `{stop: true}` JSON
object from any of the calls to the function that include a row object.
@@ -142, +149 @@

  === Sending a Redirect ===
  In the call to `_show` or when `_list` is called with a head object you can control the
headers and status code sent to the client. An example of this would be to send a redirect
notification.
  
- {{{
+ {{{#!highlight javascript
- function(doc)
+ function(doc) {
- {
-     return {"code": 302, "body": "See other", "headers": {"Location": "/"}};
+   return {"code": 302, "body": "See other", "headers": {"Location": "/"}};
  }
  }}}
  For CouchDB version 0.9:
  
- {{{
+ {{{#!highlight javascript
  function(head, row, req, row_info) {
    if (head) {
      return {"code": 302, "body": "See other", "headers": {"Location": "/"}};
@@ -163, +169 @@

  }}}
  For CouchDB version 0.10:
  
- {{{
+ {{{#!highlight javascript
  function(head, req) {
    start({"code": 302, "headers": {"Location": "/"}});
  }
  }}}
+ 
  === Specifying Content-Type Response Header ===
  There are two ways to deal with a content-type header in the response to a show or list
request. The first way is to specify the content type as a member of the _show function's
response object:
  
- {{{
+ {{{#!highlight javascript
  return {
     "headers" : {"Content-Type" : "application/xml"},
     "body" : new XML('<xml><node foo="bar"/></xml>')
  }
  }}}
+ 
  === Responding to different Content-Type Request Headers ===
  The second way to deal with content-type headers is to rely on some global helper methods
defined by CouchDB's ''<couchdb>/server/main.js'' file. The ''registerType'' method
lets you register a type key with one or more content-type strings. Please refer to the ''main.js''
file to see content-types registered by default.
  
- {{{
+ {{{#!highlight javascript
  registerType("foo", "application/foo", "application/x-foo");
  }}}
  The other global helper method for handling varying Content-Type headers is ''respondWith''.
This helper method allows you to specify different response objects depending on the type
key that corresponds to the content-type request header. The first argument is the request
object, and the second argument is a key-value object that maps type keys to functions. Each
function is expected to return an HTTP response object customized for the requested Content-Type.
  
- {{{
+ {{{#!highlight javascript
  //... in your show function...
  return respondWith(req, {
           html : function() {
@@ -203, +211 @@

  }}}
  Since CouchDB 0.10.0 there is no responseWith-Method anymore. Please use the provides Method
instead. For CouchDB version 0.10:
  
- {{{
+ {{{#!highlight javascript
  //... in your show function...
  provides("html", function() {return "<b>doc.title</b>";});
  provides("xml", function() {return "<text class="title">doc.title</text>";});

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