I made the following changes:

1.  Changed

Set mimePart.ContentType = "application/pdf"

to

Set mimePart.ContentType = "application/x-object"

2. Commented out:

Do mimeMsg.SetHeader("Content-Disposition","attachment; name=""Files1""; filename="""_docName_"""")          
Set mimeMsg.ContentTransferEncoding = "base64"

3. Uncommented:

 //Set req.ContentType = "multipart/form-data;boundary=" _mimeMsg.Boundary

After these change I received non-empty files object.

 "files": {
              "uploadedfile": "cd \\\r\n@echo start >> date.txt\r\n"
          }

Howether. Here's some tips on how to ask questions like these (with not working code samples):

1.  It must run everywhere. Remove the calls to other code (hardcode values if needed), like:

##class(HData.SiteSettings).GetFaxLogin()

2. Remove unused arguments, like coverpath

3. Remove non essential code like:

Set req.SSLConfiguration = "CardChoice"
Do req.InsertFormData("Username",##class(HData.SiteSettings).GetFaxLogin())
Do req.InsertFormData("Password",##class(HData.SiteSettings).GetFaxPassword())
Do req.InsertFormData("ProductId",##class(HData.SiteSettings).GetFaxProductId())
Do req.InsertFormData("cookies","false")
Do req.InsertFormData("header","header")

//Create job name for fax
Set sendDate = +$H
Set sendTime = $P($ZTIMESTAMP,",",2)+(15*60)
Set schedDate = $ZDATETIME(sendDate_","_sendTime,1,4)
Set schedDate = $E(schedDate,1,16)_" "_$E(schedDate,17,18)
Set docList = $LFS(docpath,"\")
Set docName = $LISTGET(docList,$LL(docList))
Do req.InsertFormData("JobName",schedDate_docName)
    
//format phone number and set billing code
Set num = $REPLACE(phone,"-","")
Do req.InsertFormData("BillingCode",num)
Do req.InsertFormData("Numbers1",num)
   
    
//get notification email
Set email = ##class(HData.SiteSettings).GetFaxNotifyEmail()
If (email '= "") Do req.InsertFormData("FeedbackEmail",email)

4. Comment out unused and misleading code paths like

Set base64 = ##class(%SYSTEM.Encryption).Base64Encode(docStream)
Set mimeMsg.ContentTransferEncoding = "base64"

5. Provide a GitHub Gist snippet of an xml file (with the code) to import and write how to run it.

Your goal, is to make it extremely easy for everyone to take a look at your snippet. All the process must consist of these two steps:

1. Drag&Drop xml file into Studio
2. Copy&Paste a line into a terminal

Since XMLEnabled class can be not persistent and, therefore, not have an extent at all, there is no such method. If you need to write  XMLExportToFile()  for several classes you can write method generator which generates a method that would:

1. Use current extent query
2. Iterate through it
3. Output each object into a file

And inherit all classes, in which you have a need of XMLExportToFile()  method from this class.

Answer

I think latency is more important than bandwith. Studio works fine on 100kb/s wireless connection, but when ping goes higher than 1s it becomes kind of slow.

Where can I find "Settings and Preferences" in Subscriptions tab under My Account?

You can open this (any) method in Studio and see the definition (with some rare exceptions, in iKnow package only  %iKnow.TextTransformation.HeaderRepositorySetArray and %iKnow.TextTransformation.KeyRepositorySetArray classes are not availible). It's the best way to get an idea of how method works and the code usually even has comments.

Scrapped from GetSimilar():

1. Select the most probably relevant terms in the source (top N)
2. Select all sources containing at least one of these N target elements
3. Sort these candidates by the number of target elements they share with the  reference documents (approximate score)
4. Of these sources, calculate the actual similarity score for the top M sources with the best approximate score
5. Now store the page window in the final result PPG

Hi. About your second question, you can easily extend Caché ObjectScript, to do it. Wouldn't recommend it for use in production, but why not add some syntax sugar on you dev instance?

Create %ZLANGC00 mac routine with the following code:

 ; %ZLANGC00
 ; custom commands for ObjectScript
 ; http://docs.intersystems.com/cache20141/csp/docbook/DocBook.UI.Page.cls?KEY=GSTU_customize
  Quit  

/// Execute Query and display the results
/// Call like this:
/// zsql "SELECT TOP 10 Name FROM Sample.Person"
ZSQL(Query)
  #Dim ResultSet As %SQL.StatementResult
  Set ResultSet = ##class(%SQL.Statement).%ExecDirect(, Query)
  Do ResultSet.%Display()
  Quit

Save and compile it and then you can execute sql in a terminal like this:

zsql "SELECT TOP 10 Name FROM Sample.Person"

It would display something like this:

SAMPLES>zsql "SELECT TOP 10 Name FROM Sample.Person"
Name
Adam,Wolfgang F.
Adams,Phil H.
Ahmed,Edward V.
Ahmed,Michael O.
Ahmed,Patrick O.
Allen,Zelda P.
Alton,Samantha F.
Bach,Buzz E.
Bach,Fred X.
Bach,Patrick Y.
 
10 Rows(s) Affected

That said I myself prefer executing SQL queries in SMP because you don't need to type them there (drag&drop from the left panel or copy&paste from the code) - it's very convenient.

The fastest query-like interface is %SQL.CustomResultSet. You need  to write your owl logic, though.

It can be called like this:

Set resultset= ##class(Package.YourCustomQueryRS).%New()
While resultset.%Next() {
   Write resultset.Id,!
}

I don't think dropdown menu items support key property. Maybe you can use id property for your purposes instead?

Is there any way to set environmental variables before calling $zf?

For example I want to add something to PATH, but if I do it in an actual $zf call it would be a lot longer and hard to read. So is there any way to set environmental variables for current process from Cache?

2016.2 Studio does not seem to have package delete button.

Just delete all contents in a package and it would disappear.  Or execute this query:

DELETE FROM %Dictionary.ClassDefinition WHERE Name %STARTSWITH 'package'

To upload images click on this button (on the WYSIWYG editor):

InterSystems University Outreach Program (Russia). Each developer has his's own machine with his own Caché/Ensemble instance. We use Git source control system and there are several Studio integration plugins we offer, but mainly Cache-tort-git. Changes are commited to a central GitHub repository preferably via pull-requests (see GitHub workflow). Changes from GitHub repository are automatically pulled to a production server(s) with Cache GitHub Continuous Integration tool.