Moving from SPServices to REST, Part 4: Converting GetListItems to REST

This entry is part 4 of 4 in the series Moving from SPServices to REST

Summary: Because of the significant inconsistencies in the SOAP Web Services, converting your calls to REST will be a different process for each of them. In this article, we’ll look at the real workhorse of SPServices: GetListItems.

When my mechanic works on my car, sometimes he tells me about some different tires or parts I might consider instead of what was on the car since I got it. It might be to improve performance or to give me a bit more life out of the car than I might get otherwise. (I have a good mechanic.)

Officina Meccanica by efilpera https://flic.kr/p/5vvSy9

Photo credit: Officina Meccanica by efilpera https://flic.kr/p/5vvSy9

As I’ve suggested in prior articles in the series, you can start moving individual calls from SOAP to REST anytime that you decide. If you’re still running an older version of SharePoint (no shame there), then it probably won’t be until you upgrade to SharePoint 2013. If you’re already on SharePoint 2010 or 2013, then you can start anytime.

When it comes time to converting some SOAP calls to REST calls, what will that process look like? In this article, we’re going to take a look at converting the workhorse of the SOAP Web Services: GetListItems.

GetListItems lets us read items from a list or library (virtually all content in SharePoint is stored in a list or library – a library is just a fancy list that is document-centric). Even basic information about users is stored in each Site Collection in the User Information List. GetListItems does a lot for us in SPServices-based development; it’s the most-commonly used function by just about every developer who uses SPServices and it sits underneath most of the value-added functions like SPCascadeDropdowns and SPDisplayRelatedItems.

The basic structure of the simplest GetListItems call is this:

$().SPServices({
  operation: "GetListItems",
  listName: "Tasks"
});

We make a call to SPServices, specify the GetListItems operation, and specify the list from which we want to get data. That’s about it. The results of this call will contain the items in the Tasks list (in the current site) as they are displayed in the Tasks list’s default view, which by default would be AllTasks.aspx.

Usually we’d have a bit more code wrapped around this call, maybe something like this:

var p = $().SPServices({
  operation: "GetListItems",
  listName: "Tasks"
});

p.done(function() {

  // Process the response

});

Note that I’m using a promise above so that I know when the call has completed rather than making a synchronous call. More on that in a later article.

So what does the analogous REST call look like? It would be something like this:

$.ajax({
  url: _spPageContextInfo.webAbsoluteUrl +
    "/_api/web/lists/getbytitle('Tasks')/items",
  method: "GET",
  headers: {
    "Accept": "application/json; odata=verbose"
  },
  success: function(data) {
    success(data); // If the call is successful, process the response
  },
  error: function(data) {
    failure(data); // Do something with the error
  }
});

Not so different when you get past the sides and trimming, right? The specifics of what we’re asking for in the REST call are all in the url object. The way REST works is that we pass information about what we want the server to do for us as parameters on the url. In this case, we have:

url: _spPageContextInfo.webAbsoluteUrl +
    "/_api/web/lists/getbytitle('Tasks')/items",

This means:

  • Go to the context of _spPageContextInfo.webAbsoluteUrl, which is the current site. In SPServices, I figure this out for you, or you can choose to specify a different site with the webURL parameter.
  • Call the lists service: /_api/web/lists
  • Select the Tasks list using its name: /getbytitle(‘Tasks’)
  • And finally, get the items: /items

The rest of the REST call is just packaging and what we want to do with the result.

Where the two methods start to diverge more is when we start to request things in more specific ways, for example all of the outstanding tasks for a particular user. But there’s an imperfect isomorphism here. For virtually everything we can do with the SOAP Web Services, we can do the same thing in REST just by adding the analogous parameters to the REST call.

Here’s how some of the most common parameters in the request payload map from SOAP to REST:

SOAP Option(SPServices synonym) REST Comments
ViewFields(CAMLViewFields) $select Choose the columns you would like to retrieve. With both SOAP and REST we get some data we don’t explicitly request, but by specifying only the columns we need we can reduce the payload sizes.
Query(CAMLQuery) $filter, $orderby Specify which items in the list we would like to return and how we would like them sorted.
RowLimit(CAMLRowLimit) $limit Say how many items matching the Query we would like to receive. In SOAP we can specify 0 to get all matching items; in REST we can omit the parameter to get all the matching items. Otherwise, we can specify any integer as the limit.
ViewName(CAMLViewName) NA ViewName lets you choose the view you would like to get in the response. There’s no REST equivalent here. I’ve always discouraged using this option in SOAP because it’s too easy to change the view settings and cause unintended consequences.
QueryOptions (CAMLQueryOptions) NA In SOAP, this lets us specify some options that change how the data is returned to us. For example, we can ask for all of the attachment URLs rather than just a Boolean which tells us that there are attachments.
NA $expand This option in REST has no direct equivalent in SOAP. $expand allows us to indicate that we would like the values for a relationship – rather than just the indices – using a projection. This is important with Lookup columns and Person or Group columns.

References:

As you can see, it’s really not that scary. It’s the equivalent of translating Spanish into French, but even easier since all of the words are in English (sorry rest of the world – I’m going to play American on this one).

Here’s a slightly more complicated example where I’m asking for items from a Workflow Tasks list.

First, the SOAP request:

SOAPRequest

And then the equivalent REST request:

REST request for items from a Workflow Tasks list

Here’s how the two calls break down based on the table I showed above:

SOAP REST
CAMLViewFields <Viewfields><FieldRef Name=’ID’/><FieldRef Name=’Title’/><FieldRef Name=’AssignedTo’/><FieldRef Name=’RelatedItems’/>

<FieldRef Name=’Priority’/>

<FieldRef Name=’Status’/>

<FieldRef Name=’DueDate’/>

<FieldRef Name=’Author’/>

</ViewFields>

$select $select=ID, Title, AssignedTo/Id, AssignedTo/Title, RelatedItems, Priority, Status, DueDate, Author/Id, Author/Title
CAMLQuery <OrderBy><FieldRef Name=’Created’ Ascending=’False’/></OrderBy> $filter, $orderby $orderby=Created Desc
NA $expand $expand=AssignedTo,Author

Note that in the SOAP call, I get the ID and Title (name) of each person or group column automatically when I request the column value. If I needed any more information about those people, I’d have to read it from another source, like the User Information List or User Profile. I also can specify a CAMLQueryOption that returns more of the basic information about users, like email address, SIP, etc.:

CAMLQueryOptions: "<QueryOptions><ExpandUserField>True</ExpandUserField></QueryOptions>"

In SOAP, most options that we pass go in the request payload. With REST, some of the options – for instance, what format we’d like the response to take – go in the request header.

If we don’t specify an accept parameter in the header, then we get XML in the response. If you’re used to parsing XML, then that might make you happy, but we usually want JSON these days.

To get JSON, we specify:

accept: application/json; odata=verbose

On premises in SharePoint 2013, this is the only option at the moment. In SharePoint Online (Office 365), if we don’t want all the metadata that comes along with the verbose option, we have a couple other options.

accept: application/json; odata=minimalmetadata
accept: application/json; odata=nometadata

The best way to understand the differences between these options is to try them out. When payload size matters (and it usually does), you should think about receiving less metadata to reduce the size of the responses.

References:

It’s the nuances that will trip us up. In SOAP, we can’t join lists together; we have to pull the data from each list and do the “join” on the client side. In REST we have what are called projections – using $expand – that let us do some lookups into other lists, for example to get information from a lookup list.

But back to GetListItems. Here are some examples of REST calls to get data back from a Tasks list showing some common parameter settings.

Get all tasks assigned to me

/_api/web/lists/getbytitle('Development Tasks')/items?$expand=AssignedTo&amp;$select=Title,AssignedTo/Title&amp;$filter=AssignedTo/Title eq 'Anderson, Marc'

Note that the format of your username will vary based on how you have things set up. Using an account may be a better choice, but I wanted to make the example clear.

Get all tasks that have not been completed, showing the status and the % complete

/_api/web/lists/getbytitle('Development Tasks')/items?$expand=AssignedTo&amp;$select=Title,AssignedTo/Title,Status,PercentComplete&amp;$filter=Status ne 'Completed'

Getting the data in these various ways is of course just the first step. Once you have the data, you’ll have to process it in some way in order to display it to the user, do calculations on it or whatever you’re trying to accomplish. That part of the exercise isn’t in the scope of this article, so you’ll have to look elsewhere for tricks for those pieces.

In the next article, we’ll look at how JavaScript promises come into play with SOAP and REST. I hope that you’ve been using promises with SPServices calls since I added support for them in version 2013.01, but if you haven’t, moving to REST is an excellent time to start doing so.

This article was first published on IT Unity on July 23, 2015. Visit the post there to read additional comments.

Retrieving Expanded Calendar Events with REST vs. SOAP

There is very little now in 2013 for which you need SPservices [sic]

from /r/sharepoint

It wouldn’t surprise you to hear that my answer to this is “it depends”. SPServices is nice in that it works the same way across SharePoint versions from 2007-2013, which might be enough reason to use it. But there are still cases where the SOAP services do something that REST doesn’t [yet] provide.

The other day I ran across an example of this. I wanted to pull events from a SharePoint calendar from today forward and I wanted to expand all of the recurring events. Since I was working on SharePoint 2013, I immediately tried to make this work using a REST call.

The first hurdle I faced was that it wasn’t possible to filter on a data like StartDate in a REST query. I know that sounds crazy, but if it’s possible I couldn’t find any way to do it.

The other challenge was the expansion of recurring events. It turned out that this was only possible using SOAP. REST doesn’t know anything about SharePoint calendar events, especially recurrence or all-day events.

I ended going back to an old thread in the SPServices discussions started by Jim Bob Howard (@jbhoward) which gives the CAML to make this work. The code I ended up with is below. In this case, I was using KnockoutJS to populate a customized view of multiple SharePoint calendars – the “rollup” idea. We’ve the various calendar locations stored in a list, and when we get to this code we have an array of calendars to work with.

// Calendar rollup
var calendars = [];
var events = [];
var calendarPromises = [];

// For each calendar, go and get the events
for (var i = 0; i < calendars.length; i++) {

  var thisCalendar = calendars[i];
  var today = moment().format();

  calendarPromises[i] = $().SPServices.SPGetListItemsJson({
      listName : thisCalendar.title,
      webURL : thisCalendar.listUrl,
      CAMLViewFields : "<ViewFields>" +
			  "<FieldRef Name='ID' />" +
			  "<FieldRef Name='Title' />" +
			  "<FieldRef Name='EventDate' />" +
			  "<FieldRef Name='EndDate' />" +
			  "<FieldRef Name='Location' />" +
			  "<FieldRef Name='Description' />" +
			  "<FieldRef Name='Category' />" +
			  "<FieldRef Name='fRecurrence' />" +
			  "<FieldRef Name='RecurrenceData' />" +
			  "<FieldRef Name='fAllDayEvent' />" +
		"</ViewFields>",
      CAMLQuery : "<Query>" +
			  "<Where>" +
				  "<And>" +
					  "<DateRangesOverlap>" +
						  "<FieldRef Name='EventDate' />" +
						  "<FieldRef Name='EndDate' />" +
						  "<FieldRef Name='RecurrenceID' />" +
							  "<Value Type='DateTime'>" +
							  "<Year />" +
						  "</Value>" +
					  "</DateRangesOverlap>" +
					  "<Or>" +
						  "<Eq>" +
							  "<FieldRef Name='HomePageHide' />" +
							  "<Value Type='Bool'>False</Value>" +
						  "</Eq>" +
						  "<IsNull>" +
							  "<FieldRef Name='HomePageHide' />" +
						  "</IsNull>" +
					  "</Or>" +
				  "</And>" +
			  "</Where>" +
			  "<OrderBy>" +
				  "<FieldRef Name='EventDate' />" +
			  "</OrderBy>" +
		"</Query>",
      CAMLQueryOptions : "<QueryOptions>" +
			  "<CalendarDate>" + today + "</CalendarDate>" +
			  "<ExpandRecurrence>TRUE</ExpandRecurrence>" +
			  "<RecurrenceOrderBy>TRUE</RecurrenceOrderBy>" +
			  "<ViewAttributes Scope='RecursiveAll'/>" +
		"</QueryOptions>",
      mappingOverrides : {
        "ows_fAllDayEvent" : {
          "mappedName" : "fAllDayEvent",
          "objectType" : "Boolean"
        },
        "ows_fRecurrence" : {
          "mappedName" : "fRecurrence",
          "objectType" : "Boolean"
        }
      }
    });

}

$.when.apply($, calendarPromises).then(function () {

  var calendarEvents = this;

  // For each calendar, go and get the items and push them into an array
  for (var i = 0; i < calendars.length; i++) {

    $(calendarEvents[i].data).each(function () {
      events.push({
        calendar : calendars[i].title,
        id : this.ID,
        title : this.Title,
        location : this.Location != null ? this.Location : "",
        category : this.Category,
        eventDate : moment(this.EventDate),
        endDate : this.EndDate,
        fAllDayEvent : this.fAllDayEvent,
        fRecurrence : this.fRecurrence,
        RecurrenceData : this.RecurrenceData
      });
    });

  }

  events.sort(function (a, b) {
    return a.eventDate.isAfter(b.eventDate) ? 1 : (a.eventDate.isBefore(b.eventDate) ? -1 : 0);
  });

  ko.applyBindings(new calendarViewModel(), document.getElementById("calendar-rollup"));

});

The code is written to handle a variable number of calendars (we started with four). Because I’m putting the promise for each call to GetListItems in the calendarPromises array, I can use

$.when.apply($, calendarPromises)

to ensure that all of the promises have been fulfilled before processing the results.

I’m also using the fantastic MomentJS library to work with dates and times. Don’t ever try to do that manually again.

I’d love to hear that I don’t need to use SOAP for this anymore, but this seems to be a case where SOAP still wins out. Maybe there’s a place for SPServices in 2013, after all.

SPTechCon Developer Days Follow Up

SPTechCon Dev DaysI got lucky on the scheduling for SPTechCon Developer Days and did both of my sessions on the first day. So today I get to attend sessions and just learn, learn, learn!

As is true of every conference the BZMedia folks put on, this one is well run and packed with excellent sessions. If you’d like to stay on top of what’s happening in the SharePoint world, sign up for their weekly SPTechReport newsletter.

Since this is a conference focused on developers, both my sessions were developer-focused. If you attended either session and have questions or feedback, feel free to get in touch.

SharePoint Evolution Conference 2015 Wrap Up

It’s been a busy few weeks in my life. First I was in London at the SharePoint Evolution Conference, then home for a week, then off to Microsoft Ignite in Chicago, then back home, and boom! I was heading out the back to put some burgers on the grill, I missed the second to the last step (of a grand total of 3!), fell, and was in excruciating pain with a broken ankle. After surgery, I’m the proud owner of some new hardware in my ankle and a 6-8 week “no weight bearing” edict.

I usually try to do a bigger write up after a great conference like SharePoint Evolution, but I’m going to flake out and just post my presentations. I do want to thank Steve Smith and Zoe Watson, along with their entire team, for an incredible experience.

New GitHub Repository for KnockoutJS Binding Handlers

KnockoutJSYesterday I created a new GitHub repo for KnockoutJS binding handlers for use with SharePoint. I’ve been using KnockoutJS for over a year now, and love working with it to build Single Page Application (SPAs) and other interactive functionality inside SharePoint.

I thought starting a repo that could store bindingHandlers for KnockoutJS that are generally useful for working with SharePoint would be useful for a lot of people.

sympmarc/KOBindings on GitHub

See the Creating custom bindings section of the KnockoutJS documentation for an overview on what binding handlers are all about.

I’ve collected some of these binding handlers and built others. Where possible, I give credit to the source in each file. Unfortunately, in my first year or so of using KnockoutJS, I collected a lot of these without maintaining the source location. If you see your work here, please let me know and I will give you credit!

  • /src contains one file per bindingHandler
  • /html contains example usage of the corresponding bindingHandler

If you’ve been working with KnockoutJS and SharePoint and would like to contribute, feel free to issue a pull request. I’m hoping this will become a repo that is useful for the SharePoint community as well as the KnockoutJS community at large.

I’m also very open to suggestions on how to structure the repo to make it optimally useful. To get things rolling, I’ve posted some of the simpler binding handlers I use, most of which help in working with jQueryUI capabilities.