Optionally writing to blob - azure-storage

I am trying to set up an azure function that would write into a blob only if a function is fulfilled. The blob is int he same location as the function, so I am trying to avoid providing a connection string and do this with bindings. I am currently using binding something like the following:
[Blob("folder/myFile.json", FileAccess.Write)]Stream writeBlob
With this binding, I can write into the JSON file using:
if (myCondition)
using (var writer = new StreamWriter(writeBlob))
writer.Write(myContent);
This works fine when the condition is true. However, when the condition is false, the file gets empty. Since I am not writing to the stream, I expected the file to stay untouched. Right now my workaround is to have another read binding to the same json and rewrite the file contents.

You can use dynamic binding in your case. See this post for more information:
How do I use Binder to perform dynamic bindings in my C# Function?
So basically you need to:
Add a IBinder binder parameter in your function definition.
When your condition is true, write your file:
if (myCondition)
{
var binding= new BlobAttribute(blobPath: "folder/myFile.json");
using (var writer = binder.Bind<TextWriter>(binding))
{
writer.Write(myContent);
}
}

Related

Google diff-match-patch : How to unpatch to get Original String?

I am using Google diff-match-patch JAVA plugin to create patch between two JSON strings and storing the patch to database.
diff_match_patch dmp = new diff_match_patch();
LinkedList<Patch> diffs = dmp.patch_make(latestString, originalString);
String patch = dmp.patch_toText(diffs); // Store patch to DB
Now is there any way to use this patch to re-create the originalString by passing the latestString?
I google about this and found this very old comment # Google diff-match-patch Wiki saying,
Unpatching can be done by just looping through the diff, swapping
DIFF_INSERT with DIFF_DELETE, then applying the patch.
But i did not find any useful code that demonstrates this. How could i achieve this with my existing code ? Any pointers or code reference would be appreciated.
Edit:
The problem i am facing is, in the front-end i am showing a revisions module that shows all the transactions of a particular fragment (take for example an employee details), like which user has updated what details etc. Now i am recreating the fragment JSON by reverse applying each patch to get the current transaction data and show it as a table (using http://marianoguerra.github.io/json.human.js/). But some JSON data are not valid JSON and I am getting JSON.parse error.
I was looking to do something similar (in C#) and what is working for me with a relatively simple object is the patch_apply method. This use case seems somewhat missing from the documentation, so I'm answering here. Code is C# but the API is cross language:
static void Main(string[] args)
{
var dmp = new diff_match_patch();
string v1 = "My Json Object;
string v2 = "My Mutated Json Object"
var v2ToV1Patch = dmp.patch_make(v2, v1);
var v2ToV1PatchText = dmp.patch_toText(v2ToV1Patch); // Persist text to db
string v3 = "Latest version of JSON object;
var v3ToV2Patch = dmp.patch_make(v3, v2);
var v3ToV2PatchTxt = dmp.patch_toText(v3ToV2Patch); // Persist text to db
// Time to re-hydrate the objects
var altV3ToV2Patch = dmp.patch_fromText(v3ToV2PatchTxt);
var altV2 = dmp.patch_apply(altV3ToV2Patch, v3)[0].ToString(); // .get(0) in Java I think
var altV2ToV1Patch = dmp.patch_fromText(v2ToV1PatchText);
var altV1 = dmp.patch_apply(altV2ToV1Patch, altV2)[0].ToString();
}
I am attempting to retrofit this as an audit log, where previously the entire JSON object was saved. As the audited objects have become more complex the storage requirements have increased dramatically. I haven't yet applied this to the complex large objects, but it is possible to check if the patch was successful by checking the second object in the array returned by the patch_apply method. This is an array of boolean values, all of which should be true if the patch worked correctly. You could write some code to check this, which would help check if the object can be successfully re-hydrated from the JSON rather than just getting a parsing error. My prototype C# method looks like this:
private static bool ValidatePatch(object[] patchResult, out string patchedString)
{
patchedString = patchResult[0] as string;
var successArray = patchResult[1] as bool[];
foreach (var b in successArray)
{
if (!b)
return false;
}
return true;
}

Datatables: How to reload server-side data with additional params

I have a table which gets its data server-side, using custom server-side initialization params which vary depending upon which report is produced. Once the table is generated, the user may open a popup in which they can add multiple additional filters on which to search. I need to be able to use the same initialization params as the original table, and add the new ones using fnServerParams.
I can't figure out how to get the original initialization params using the datatables API. I had thought I could get a reference to the object, get the settings using fnSettings, and pass those settings into a new datatables instance like so:
var oSettings = $('#myTable').dataTable().fnSettings();
// add additional params to the oSettings object
$('#myTable').dataTable(oSettings);
but the variable returned through fnSettings isn't what I need and doesn't work.
At this point, it seems like I'm going to re-architect things so that I can pass the initialization params around as a variable and add params as needed, unless somebody can steer me in the right direction.
EDIT:
Following tduchateau's answer below, I was able to get partway there by using
var oTable= $('#myTable').dataTable(),
oSettings = oTable.fnSettings(),
oParams = oTable.oApi._fnAjaxParameters(oSettings);
oParams.push('name':'my-new-filter', 'value':'my-new-filter-value');
and can confirm that my new serverside params are added on to the existing params.
However, I'm still not quite there.
$('#myTable').dataTable(oSettings);
gives the error:
DataTables warning(table id = 'myTable'): Cannot reinitialise DataTable.
To retrieve the DataTables object for this table, please pass either no arguments
to the dataTable() function, or set bRetrieve to true.
Alternatively, to destroy the old table and create a new one, set bDestroy to true.
Setting
oTable.bRetrieve = true;
doesn't get rid of the error, and setting
oSettings.bRetrieve = true;
causes the table to not execute the ajax call. Setting
oSettings.bDestroy = true;
loses all the custom params, while setting
oTable.bDestroy = true;
returns the above error. And simply calling
oTable.fnDraw();
causes the table to be redrawn with its original settings.
Finally got it to work using fnServerParams. Note that I'm both deleting unneccessary params and adding new ones, using a url var object:
"fnServerParams": function ( aoData ) {
var l = aoData.length;
// remove unneeded server params
for (var i = 0; i < l; ++i) {
// if param name starts with bRegex_, sSearch_, mDataProp_, bSearchable_, or bSortable_, remove it from the array
if (aoData[i].name.search(/bRegex_|sSearch_|mDataProp_|bSearchable_|bSortable_/) !== -1 ){
aoData.splice(i, 1);
// since we've removed an element from the array, we need to decrement both the index and the length vars
--i;
--l;
}
}
// add the url variables to the server array
for (i in oUrlvars) {
aoData.push( { "name": i, "value": oUrlvars[i]} );
}
}
This is normally the right way to retrieve the initialization settings:
var oSettings = oTable.fnSettings();
Why is it not what you need? What's wrong with these params?
If you need to filter data depending on your additional filters, you can complete the array of "AJAX data" sent to the server using this:
var oTable = $('#myTable').dataTable();
var oParams = oTable.oApi._fnAjaxParameters( oTable );
oParams.push({name: "your-additional-param-name", value: your-additional-param-value });
You can see some example usages in the TableTools plugin.
But I'm not sure this is what you need... :-)

List of DisposableLazy`2 does not have 'Add' method when called using dynamic variable

Problem
I am facing a problem using dynamically created list of items when Add method is called on dynamicvariable. Consider following code.
IEnumerable<dynamic> plugins = (IEnumerable<dynamic>)field.GetValue(instance);
if (plugins == null)
continue;
dynamic filteredPlugins = null;
foreach (var plugin in plugins)
{
if (filteredPlugins == null)
filteredPlugins = Activator
.CreateInstance(typeof(List<>)
.MakeGenericType(plugin.GetType()));
if (/* this condition does not matter*/)
//filteredPlugins.Add(plugin);
filteredPlugins.GetType().GetMethod("Add")
.Invoke(filteredPlugins, new object[] { plugin });
}
And now, the commented line filteredPlugins.Add(plugin) will throw System.Reflection.TargetInvocationException with the message 'object' does not contain a definition for 'Add' when plugin is of type
System.ComponentModel.Composition.ExportServices.DisposableLazy<IPlugin,IMetadata>
but it works completely perfect when pluginis of type
System.Lazy<IPlugin, IMetadata>
When the reflection is used to call Add method on the instance filteredPlugins instance as is done on the next line - everything works fine for any type.
My question is WHY is not Add method found in case of DisposableLazy type.
Background
This code is part of the method that I use in OnImportsSatisfied() method. I am using two kinds of import - which differs only in RequiredCreationPolicy - on has CreationPolicy.NonShared and the other default value of CreationPolicy.Any.
[ImportMany(RequiredCreationPolicy = CreationPolicy.NonShared)]
private IEnumerable<Lazy<IPlugin, IMetadata>> plugins = null;
For CreationPolicy.NonShared fields the underlaying type in the plugins is DisposableLazy and for CreationPolicy.Any the underlaying type in the plugins is Lazy.
Edit: As asked in the answer - I am using dynamic variable because IPlugin interface can change everytime this method is called and they do not have to have anything in common.
Edit2: I just found similar question C# dynamic type gotcha, so this can be probably closed as duplicite.
Because System.ComponentModel.Composition.ExportServices.DisposableLazy is a private class, the runtime binder is having trouble believing you have permission to use type, where reflection doesn't care.
Which begs the question why are you using dynamics at all in this case. Since DisposableLazy<IPlugin,IMetadata> public interface is it's subclass Lazy<IPlugin, IMetadata> & IDisposable, shouldn't you just be using a List<Lazy<IPlugin, IMetadata>> for either case?
var plugins = (IEnumerable<Lazy<IPlugin, IMetadata>>)field.GetValue(instance);
if (plugins == null)
continue;
var filteredPlugins = new List<Lazy<IPlugin, IMetadata>>();
foreach (var plugin in plugins)
{
if (/* this condition does not matter*/)
filteredPlugins.Add(plugin);
}
}

An interesting Restlet Attribute behavior

Using Restlet 2.1 for Java EE, I am discovering an interesting problem with its ability to handle attributes.
Suppose you have code like the following:
cmp.getDefaultHost().attach("/testpath/{attr}",SomeServerResource.class);
and on your browser you provide the following URL:
http://localhost:8100/testpath/command
then, of course, the attr attribute gets set to "command".
Unfortunately, suppose you want the attribute to be something like command/test, as in the following URL:
http://localhost:8100/testpath/command/test
or if you want to dynamically add things with different levels, like:
http://localhost:800/testpath/command/test/subsystems/network/security
in both cases the attr attribute is still set to "command"!
Is there some way in a restlet application to make an attribute that can retain the "slash", so that one can, for example, make the attr attribute be set to "command/test"? I would like to be able to just grab everything after testpath and have the entire string be the attribute.
Is this possible? Someone please advise.
For the same case I usually change the type of the variable :
Route route = cmp.getDefaultHost().attach("/testpath/{attr}",SomeServerResource.class);
route.getTemplate().getVariables().get("attr") = new Variable(Variable.TYPE_URI_PATH);
You can do this by using url encoding.
I made the following attachment in my router:
router.attach("/test/{cmd}", TestResource.class);
My test resource class looks like this, with a little help from Apache Commons Codec URLCodec
#Override
protected Representation get() {
try {
String raw = ResourceWrapper.get(this, "cmd");
String decoded = new String(URLCodec.decodeUrl(raw.getBytes()));
return ResourceWrapper.wrap(raw + " " + decoded);
} catch(Exception e) { throw new RuntimeException(e); }
}
Note my resource wrapper class is simply utility methods. The get returns the string of the url param, and the wrap returns a StringRepresentation.
Now if I do something like this:
http://127.0.0.1/test/haha/awesome
I get a 404.
Instead, I do this:
http://127.0.0.1/test/haha%2fawesome
I have URLEncoded the folder path. This results in my browser saying:
haha%2fawesome haha/awesome
The first is the raw string, the second is the result. I don't know if this is suitable for your needs as it's a simplistic example, but as long as you URLEncode your attribute, you can decode it on the other end.

Returning wcf/json result from the wcf service

I Need by service contract to return the xml/json result depending on the request type.I also need a kind of helper function which will convert my result set (i am using linq to sql) so that i do not need to create the xml format for the result set by iterating through the table row many times.What is the suitable way to do that.
I need a kind of short cut method which will convert the table data to xml result.Had i been using asp.net mvc i would have been able to generate the xml data by overriding the the ExecuteResult method in the ActionResult and giving Conetnt-Type = "text/xml" as OP.But since i am using
Wcf i don't have the controller context(as controller context is the parameter that needs to be passed to Execute Result).
My present code for converting the table data to the xml format is below.
public XDocument UsersLists(string authToken)
{
bool IsAuthenticated = Authenticate(authToken);
XDocument xDoc = new XDocument();
XElement root = new XElement("Users");
if (IsAuthenticated)
{
List<User> lstUsers = _lService.UserRepository.GetUserCompanyFromAccountID(GetAccountId(authToken)).ToList();
if (lstUsers != null)
{
root.Add(new XElement("Message", "Success"));
foreach (var u in lstUsers)
{
XElement chid = new XElement("User");
root.Add(new XElement("UserId", u.UserId));
root.Add(new XElement("FirstName", u.FirstName));
root.Add(new XElement("LastName", u.LastName));
root.Add(new XElement("Email", u.Email));
root.Add(new XElement("CompanyName", u.Company.CompanyName));
root.Add(chid);
}
xDoc.Add(root);
return xDoc;
}
else
{
return ReturnFailure(xDoc, root);
}
}
else
{
return ReturnFailure(xDoc, root);
}
}
I need to eliminate this way of generating xml for each table records.
An early response is priceless.
Thanks
Technology : Windows Communication Foundation.
Implementation of single operation returning both XML or JSON differs between WCF 3.5 or WCF 4.0. For implementing this feature in WCF 3.5 check this thread. Generally you will have to create custom behavior and set the content type based on Accept header from the request. WCF 4.0 has native support for this feature. WebHttpBehavior has property AutomaticFormatSelectionEnabled. If you set this property to true it should just work out of the box.
To your second question. You don't need any custom formatting like in ASP.NET MVC. Formatting in WCF is handled by serialization. Just return collection from your operation and you will see what happens. Linq-To-Sql generated entities should be serializable by default. Just don't forget to execute query before returning from method. If you need special format of date which is not the same as Linq-To-Sql entities create custom data type which have public parameterless constructor and all required properties with getter and setter. If you want to make it clear makr that class with DataContract attribute and all properties with DataMember attribute. Return collection of that custom class instances from your operation.