blob | 易学教程

Python: use requests to read an image (url), then save as BLOB data to MySQL

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问题 Suppose I'm using requests to open an image url and read the data, save as BLOB data to MySQL, what is the most efficient way of doing it? I did some search and looks like PIL.Image & StringIO method is recommended, as in this document : http://docs.python-requests.org/en/latest/user/quickstart/#binary-response-content There are some other methods, as mentioned in this question : How do I read image data from a URL in Python? However, I seem to be using a "simpler" way of implementing the

DataURI to Blob errors: DOM Exception 5: An invalid or illegal character was specified

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问题 I'm using Meteor with a Cordova plugin to record a video on an iPhone, then convert that to a blob for uploading. About half of the time I try to convert the video from the local filesystem to a blob it works and the other half it gives this error: InvalidCharacterError: DOM Exception 5: An invalid or illegal character was specified, such as in an XML name. It seems like it usually happens when the video is longer than 3 seconds, but it has happened on the really short videos. Here is my

Html5 video blob on iOS 9

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问题 Loading a video (mp4/H264) to a blob through xhr, then using such blob as the source for an HTML5 Video element. var vsource = window.URL.createObjectURL(blob); var player = document.getElementById("player"); player.src = vsource; player.play(); The above has been working on pretty much every major desktop and mobile browser, with the exception of iOS Safari. It was broken on iOS 7, worked on iOS 8, and stopped working again on iOS 9. I wonder if anyone is aware of this, and if there is any

Caffe源码-LossLayer类（下）

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InfogainLossLayer类 EuclideanLossLayer类 HingeLossLayer类 ContrastiveLossLayer类 InfogainLossLayer类简介 InfogainLossLayer与SoftmaxWithLossLayer类似，只不过增加了一个信息增益矩阵 \(H\) ，用于指定某真实类别的数据被预测为某一类别时的权重，常用于类间样本数不均衡的情况。当矩阵 \(H\) 为单位矩阵时，等同于SoftmaxWithLossLayer。第一个输入blob为网络的预测值，大小 \(\tilde{N} \times C \times \tilde H \times \tilde W\) ，范围 \(x_{n,k} \in [-\infty, +\infty]\) 。计算loss时使用softmax函数值作为其概率， \(\hat{p}_{n,k} = \frac{e^{x_{n,k}}}{\sum\limits_{k'=1}^{K} e^{x_{n,k'}}}\) 。后续假设计算softmax时是沿着第1维（维度 \(C\) ）进行的，则维度 \(C\) 的大小即为类别总数 \(K\) ，数据的总个数为外部个数（对应代码中的 outer_num_ ）乘上内部个数 inner_num_ ，即 \(N=\tilde N * \tilde

MySQL / MariaDB unique BLOB of fixed length

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问题 I need a 16-byte binary data column to be unique. Why can't a BLOB(16) be unique in MySQL and MariaDB, when it supports unique VARCHAR? That this is supported but not a fixed-length set of bytes seems nuts. Also, it's not acceptable to waste space by storing a binary value in base64 encoded strings. So, any better option than converting to/from two BIGINTs that make a composite unique index (this 16-byte binary is not used as a primary key, if it matters)? (Also, if I do use two BIGINTs, does

Concatenate TStringStream

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问题 I would like to concatenate some TStringStreams into one Stream. I have some blob (varbinary(max)) fields in SQL Server and and I want to create a stream from all the rows then save it to a file. var // MSWord: Variant; i: Int32; sA: TStringStream; sP: TStringStream; s: TStringStream; // fString: TStrings; begin sA := TStringStream.Create; s := TStringStream.Create; sP := TStringStream.Create; try with DateED do begin BlobField.SaveToStream(sA); sA.SaveToStream(s); // s.CopyFrom(sA, sA.Size);

Creating blob (Oracle) returns “Method is not implemented by JDBC driver” (Jboss eap 5.1)

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问题 I have Blob bl = pstmt.getConnection().createBlob(); a code where it is trying to create/save a blob in Oracle: returning the following error: "Method is not implemented by JDBC driver" That is the message I am getting, cant see more. The application is in a Jboss EAP 5.1 with the following changes: - jboss-common-jdbc-wrapper.jar --changed--> jboss-as-connector-6.1.0.final-jboss-common-jdbc-wrapper.jar - server/all/lib/ojdbc6.jar Which can be the problem? 回答1: This is a JDBC version / JDBC

Creating blob (Oracle) returns “Method is not implemented by JDBC driver” (Jboss eap 5.1)

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java insert Blob as ByteArrayOutputStream get ClassCastException

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问题 I've to save a pdf file represented as a ByteArrayOutputStream into a Blob SQL field of a table, here's my code: public boolean savePDF(int version, ByteArrayOutputStream baos) throws Exception{ boolean completed = false; ConnectionManager conn = new ConnectionManager(); try { PreparedStatement statement = conn.getConnection().prepareStatement(INSERT_PDF); statement.setLong(1, version); statement.setBlob(2, (Blob)baos); statement.execute(); conn.commit(); completed = true; } catch

Windows azure CDN blob transactions bill

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问题 If I have an icon, 'icon.png' that will be served from the CDN. It is 1K and cached for long time. 1M users hit it from every location in the world. Q1: because the request is cached 304 on client side will Azure bill me for request when the CLIENT visit my second page and same icon.png served from the cache? in the bill I will have 1M transactions OR 1M transactions MULTIPLY by Page view? Please share average price what you pay for 10000 daily users let say 10 page views per user I need to